Merge pull request #14834 from esphome/bump-2026.3.0b2

2026.3.0b2

Doxyfile

@@ -48,7 +48,7 @@ PROJECT_NAME           = ESPHome
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 2026.3.0b1
+PROJECT_NUMBER         = 2026.3.0b2
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a

esphome/components/adc/adc_sensor_rp2040.cpp

@@ -8,6 +8,13 @@
 #endif  // CYW43_USES_VSYS_PIN
 #include <hardware/adc.h>
 
+// PICO_VSYS_PIN is defined in pico-sdk board headers (e.g. boards/pico2.h),
+// but the Arduino framework's config_autogen.h includes a generic board header
+// that doesn't define it. Provide the standard value (pin 29) as a fallback.
+#ifndef PICO_VSYS_PIN
+#define PICO_VSYS_PIN 29  // NOLINT(cppcoreguidelines-macro-usage)
+#endif
+
 namespace esphome {
 namespace adc {
 

esphome/components/addressable_light/addressable_light_display.h

@@ -33,7 +33,7 @@ class AddressableLightDisplay : public display::DisplayBuffer {
         // - Save the current effect index.
         this->last_effect_index_ = light_state_->get_current_effect_index();
         // - Disable any current effect.
-        light_state_->make_call().set_effect(0).perform();
+        light_state_->make_call().set_effect(uint32_t{0}).perform();
       }
     }
     enabled_ = enabled;

esphome/components/api/api_connection.h

@@ -14,6 +14,12 @@
 #include "api_server.h"
 #include "esphome/core/application.h"
 #include "esphome/core/component.h"
+#ifdef USE_ESP32_CRASH_HANDLER
+#include "esphome/components/esp32/crash_handler.h"
+#endif
+#ifdef USE_RP2040_CRASH_HANDLER
+#include "esphome/components/rp2040/crash_handler.h"
+#endif
 #include "esphome/core/entity_base.h"
 #include "esphome/core/string_ref.h"
 
@@ -235,6 +241,12 @@ class APIConnection final : public APIServerConnectionBase {
     this->flags_.log_subscription = msg.level;
     if (msg.dump_config)
       App.schedule_dump_config();
+#ifdef USE_ESP32_CRASH_HANDLER
+    esp32::crash_handler_log();
+#endif
+#ifdef USE_RP2040_CRASH_HANDLER
+    rp2040::crash_handler_log();
+#endif
   }
 #ifdef USE_API_HOMEASSISTANT_SERVICES
   void on_subscribe_homeassistant_services_request() override { this->flags_.service_call_subscription = true; }

esphome/components/api/api_frame_helper.h

@@ -134,12 +134,16 @@ class APIFrameHelper {
   //
   // For log messages: Use Nagle to coalesce multiple small log packets into
   // fewer larger packets, reducing WiFi overhead. However, we limit batching
-  // to 3 messages to avoid excessive LWIP buffer pressure on memory-constrained
-  // devices like ESP8266. LWIP's TCP_OVERSIZE option coalesces the data into
-  // shared pbufs, but holding data too long waiting for Nagle's timer causes
-  // buffer exhaustion and dropped messages.
+  // to avoid excessive LWIP buffer pressure on memory-constrained devices.
+  // LWIP's TCP_OVERSIZE option coalesces the data into shared pbufs, but
+  // holding data too long waiting for Nagle's timer causes buffer exhaustion
+  // and dropped messages.
   //
-  // Flow: Log 1 (Nagle on) -> Log 2 (Nagle on) -> Log 3 (NODELAY, flush all)
+  // ESP32 (TCP_SND_BUF=4×MSS+) / RP2040 (8×MSS) / LibreTiny (4×MSS): 4 logs per cycle
+  // ESP8266 (2×MSS): 3 logs per cycle (tightest buffers)
+  //
+  // Flow (ESP32/RP2040/LT): Log 1 (Nagle on) -> Log 2 -> Log 3 -> Log 4 (NODELAY, flush)
+  // Flow (ESP8266):         Log 1 (Nagle on) -> Log 2 -> Log 3 (NODELAY, flush all)
   //
   void set_nodelay_for_message(bool is_log_message) {
     if (!is_log_message) {
@@ -150,7 +154,7 @@ class APIFrameHelper {
       return;
     }
 
-    // Log messages 1-3: state transitions -1 -> 1 -> 2 -> -1 (flush on 3rd)
+    // Log messages: state transitions -1 -> 1 -> ... -> LOG_NAGLE_COUNT -> -1 (flush)
     if (this->nodelay_state_ == NODELAY_ON) {
       this->set_nodelay_raw_(false);
       this->nodelay_state_ = 1;
@@ -255,10 +259,16 @@ class APIFrameHelper {
   uint8_t tx_buf_tail_{0};
   uint8_t tx_buf_count_{0};
   // Nagle batching state for log messages. NODELAY_ON (-1) means NODELAY is enabled
-  // (immediate send). Values 1-2 count log messages in the current Nagle batch.
+  // (immediate send). Values 1..LOG_NAGLE_COUNT count log messages in the current Nagle batch.
   // After LOG_NAGLE_COUNT logs, we switch to NODELAY to flush and reset.
+  // ESP8266 has the tightest TCP send buffer (2×MSS) and needs conservative batching.
+  // ESP32 (4×MSS+), RP2040 (8×MSS), and LibreTiny (4×MSS) can coalesce more.
   static constexpr int8_t NODELAY_ON = -1;
+#ifdef USE_ESP8266
   static constexpr int8_t LOG_NAGLE_COUNT = 2;
+#else
+  static constexpr int8_t LOG_NAGLE_COUNT = 3;
+#endif
   int8_t nodelay_state_{NODELAY_ON};
 
   // Internal helper to set TCP_NODELAY socket option

esphome/components/api/api_frame_helper_noise.cpp

@@ -258,10 +258,13 @@ APIError APINoiseFrameHelper::state_action_() {
     // ignore contents, may be used in future for flags
     // Resize for: existing prologue + 2 size bytes + frame data
     size_t old_size = this->prologue_.size();
-    this->prologue_.resize(old_size + 2 + this->rx_buf_.size());
-    this->prologue_[old_size] = (uint8_t) (this->rx_buf_.size() >> 8);
-    this->prologue_[old_size + 1] = (uint8_t) this->rx_buf_.size();
-    std::memcpy(this->prologue_.data() + old_size + 2, this->rx_buf_.data(), this->rx_buf_.size());
+    size_t rx_size = this->rx_buf_.size();
+    this->prologue_.resize(old_size + 2 + rx_size);
+    this->prologue_[old_size] = (uint8_t) (rx_size >> 8);
+    this->prologue_[old_size + 1] = (uint8_t) rx_size;
+    if (rx_size > 0) {
+      std::memcpy(this->prologue_.data() + old_size + 2, this->rx_buf_.data(), rx_size);
+    }
 
     state_ = State::SERVER_HELLO;
   }

esphome/components/api/api_pb2_dump.cpp

@@ -13,7 +13,7 @@ namespace esphome::api {
 static inline void append_quoted_string(DumpBuffer &out, const StringRef &ref) {
   out.append("'");
   if (!ref.empty()) {
-    out.append(ref.c_str());
+    out.append(ref.c_str(), ref.size());
   }
   out.append("'");
 }

esphome/components/api/client.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 import asyncio
 from datetime import datetime
+import importlib
 import logging
 from typing import TYPE_CHECKING, Any
 import warnings
@@ -18,6 +19,7 @@ import contextlib
 
 from esphome.const import CONF_KEY, CONF_PORT, __version__
 from esphome.core import CORE
+from esphome.platformio_api import process_stacktrace
 
 from . import CONF_ENCRYPTION
 
@@ -55,9 +57,19 @@ async def async_run_logs(config: dict[str, Any], addresses: list[str]) -> None:
         addresses=addresses,  # Pass all addresses for automatic retry
     )
     dashboard = CORE.dashboard
+    backtrace_state = False
+
+    # Try platform-specific stacktrace handler first, fall back to generic
+    platform_process_stacktrace = None
+    try:
+        module = importlib.import_module("esphome.components." + CORE.target_platform)
+        platform_process_stacktrace = getattr(module, "process_stacktrace")
+    except (AttributeError, ImportError):
+        pass
 
     def on_log(msg: SubscribeLogsResponse) -> None:
         """Handle a new log message."""
+        nonlocal backtrace_state
         time_ = datetime.now()
         message: bytes = msg.message
         text = message.decode("utf8", "backslashreplace")
@@ -67,6 +79,15 @@ async def async_run_logs(config: dict[str, Any], addresses: list[str]) -> None:
         )
         for parsed_msg in parse_log_message(text, timestamp):
             print(parsed_msg.replace("\033", "\\033") if dashboard else parsed_msg)
+        for raw_line in text.splitlines():
+            if platform_process_stacktrace:
+                backtrace_state = platform_process_stacktrace(
+                    config, raw_line, backtrace_state
+                )
+            else:
+                backtrace_state = process_stacktrace(
+                    config, raw_line, backtrace_state=backtrace_state
+                )
 
     stop = await async_run(cli, on_log, name=name)
     try:

esphome/components/audio/__init__.py

@@ -214,4 +214,4 @@ async def to_code(config):
         cg.add_define("USE_AUDIO_MP3_SUPPORT")
     if data.opus_support:
         cg.add_define("USE_AUDIO_OPUS_SUPPORT")
-        add_idf_component(name="esphome/micro-opus", ref="0.3.4")
+        add_idf_component(name="esphome/micro-opus", ref="0.3.5")

esphome/components/captive_portal/captive_portal.cpp

@@ -61,7 +61,7 @@ void CaptivePortal::handle_wifisave(AsyncWebServerRequest *request) {
   // Defer save to main loop thread to avoid NVS operations from HTTP thread
   this->defer([ssid, psk]() { wifi::global_wifi_component->save_wifi_sta(ssid.c_str(), psk.c_str()); });
 #endif
-  request->redirect(ESPHOME_F("/?save"));
+  request->send(200, ESPHOME_F("text/plain"), ESPHOME_F("Saved. Connecting..."));
 }
 
 void CaptivePortal::setup() {
@@ -71,7 +71,7 @@ void CaptivePortal::setup() {
 void CaptivePortal::start() {
   this->base_->init();
   if (!this->initialized_) {
-    this->base_->add_handler(this);
+    this->base_->add_handler_without_auth(this);
   }
 
   network::IPAddress ip = wifi::global_wifi_component->wifi_soft_ap_ip();

esphome/components/debug/debug_component.h

@@ -18,6 +18,7 @@ namespace debug {
 
 static constexpr size_t DEVICE_INFO_BUFFER_SIZE = 256;
 static constexpr size_t RESET_REASON_BUFFER_SIZE = 128;
+static constexpr size_t WAKEUP_CAUSE_BUFFER_SIZE = 128;
 
 // buf_append_printf is now provided by esphome/core/helpers.h
 
@@ -94,7 +95,7 @@ class DebugComponent : public PollingComponent {
 #endif  // USE_TEXT_SENSOR
 
   const char *get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer);
-  const char *get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer);
+  const char *get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE> buffer);
   uint32_t get_free_heap_();
   size_t get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE> buffer, size_t pos);
   void update_platform_();

esphome/components/debug/debug_esp32.cpp

@@ -98,7 +98,7 @@ static const char *const WAKEUP_CAUSES[] = {
     "BT",
 };
 
-const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
+const char *DebugComponent::get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE> buffer) {
   const char *wake_reason;
   unsigned reason = esp_sleep_get_wakeup_cause();
   if (reason < sizeof(WAKEUP_CAUSES) / sizeof(WAKEUP_CAUSES[0])) {
@@ -196,9 +196,10 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
   uint32_t cpu_freq_mhz = arch_get_cpu_freq_hz() / 1000000;
   pos = buf_append_printf(buf, size, pos, "|CPU Frequency: %" PRIu32 " MHz", cpu_freq_mhz);
 
-  char reason_buffer[RESET_REASON_BUFFER_SIZE];
-  const char *reset_reason = get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE>(reason_buffer));
-  const char *wakeup_cause = get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE>(reason_buffer));
+  char reset_buffer[RESET_REASON_BUFFER_SIZE];
+  char wakeup_buffer[WAKEUP_CAUSE_BUFFER_SIZE];
+  const char *reset_reason = get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE>(reset_buffer));
+  const char *wakeup_cause = get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE>(wakeup_buffer));
 
   uint8_t mac[6];
   get_mac_address_raw(mac);

esphome/components/debug/debug_esp8266.cpp

@@ -91,7 +91,7 @@ const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFE
   return buffer.data();
 }
 
-const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
+const char *DebugComponent::get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE> buffer) {
   // ESP8266 doesn't have detailed wakeup cause like ESP32
   return "";
 }

esphome/components/debug/debug_host.cpp

@@ -7,7 +7,7 @@ namespace debug {
 
 const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) { return ""; }
 
-const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) { return ""; }
+const char *DebugComponent::get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE> buffer) { return ""; }
 
 uint32_t DebugComponent::get_free_heap_() { return INT_MAX; }
 

esphome/components/debug/debug_libretiny.cpp

@@ -12,7 +12,7 @@ const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFE
   return lt_get_reboot_reason_name(lt_get_reboot_reason());
 }
 
-const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) { return ""; }
+const char *DebugComponent::get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE> buffer) { return ""; }
 
 uint32_t DebugComponent::get_free_heap_() { return lt_heap_get_free(); }
 

esphome/components/debug/debug_rp2040.cpp

@@ -1,23 +1,81 @@
 #include "debug_component.h"
 #ifdef USE_RP2040
+#include "esphome/core/defines.h"
 #include "esphome/core/log.h"
 #include <Arduino.h>
+#include <hardware/watchdog.h>
+#if defined(PICO_RP2350)
+#include <hardware/structs/powman.h>
+#else
+#include <hardware/structs/vreg_and_chip_reset.h>
+#endif
+#ifdef USE_RP2040_CRASH_HANDLER
+#include "esphome/components/rp2040/crash_handler.h"
+#endif
 namespace esphome {
 namespace debug {
 
 static const char *const TAG = "debug";
 
-const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) { return ""; }
+const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
+  char *buf = buffer.data();
+  const size_t size = RESET_REASON_BUFFER_SIZE;
+  size_t pos = 0;
 
-const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) { return ""; }
+#if defined(PICO_RP2350)
+  uint32_t chip_reset = powman_hw->chip_reset;
+  if (chip_reset & 0x04000000)  // HAD_GLITCH_DETECT
+    pos = buf_append_str(buf, size, pos, "Power supply glitch|");
+  if (chip_reset & 0x00040000)  // HAD_RUN_LOW
+    pos = buf_append_str(buf, size, pos, "RUN pin|");
+  if (chip_reset & 0x00020000)  // HAD_BOR
+    pos = buf_append_str(buf, size, pos, "Brown-out|");
+  if (chip_reset & 0x00010000)  // HAD_POR
+    pos = buf_append_str(buf, size, pos, "Power-on reset|");
+#else
+  uint32_t chip_reset = vreg_and_chip_reset_hw->chip_reset;
+  if (chip_reset & 0x00010000)  // HAD_RUN
+    pos = buf_append_str(buf, size, pos, "RUN pin|");
+  if (chip_reset & 0x00000100)  // HAD_POR
+    pos = buf_append_str(buf, size, pos, "Power-on reset|");
+#endif
 
-uint32_t DebugComponent::get_free_heap_() { return rp2040.getFreeHeap(); }
+  if (watchdog_caused_reboot()) {
+    bool handled = false;
+#ifdef USE_RP2040_CRASH_HANDLER
+    if (rp2040::crash_handler_has_data()) {
+      pos = buf_append_str(buf, size, pos, "Crash (HardFault)|");
+      handled = true;
+    }
+#endif
+    if (!handled) {
+      if (watchdog_enable_caused_reboot()) {
+        pos = buf_append_str(buf, size, pos, "Watchdog timeout|");
+      } else {
+        pos = buf_append_str(buf, size, pos, "Software reset|");
+      }
+    }
+  }
+
+  // Remove trailing '|'
+  if (pos > 0 && buf[pos - 1] == '|') {
+    buf[pos - 1] = '\0';
+  } else if (pos == 0) {
+    return "Unknown";
+  }
+
+  return buf;
+}
+
+const char *DebugComponent::get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE> buffer) { return ""; }
+
+uint32_t DebugComponent::get_free_heap_() { return ::rp2040.getFreeHeap(); }
 
 size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE> buffer, size_t pos) {
   constexpr size_t size = DEVICE_INFO_BUFFER_SIZE;
   char *buf = buffer.data();
 
-  uint32_t cpu_freq = rp2040.f_cpu();
+  uint32_t cpu_freq = ::rp2040.f_cpu();
   ESP_LOGD(TAG, "CPU Frequency: %" PRIu32, cpu_freq);
   pos = buf_append_printf(buf, size, pos, "|CPU Frequency: %" PRIu32, cpu_freq);
 

esphome/components/debug/debug_zephyr.cpp

@@ -53,7 +53,7 @@ const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFE
   return buf;
 }
 
-const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
+const char *DebugComponent::get_wakeup_cause_(std::span<char, WAKEUP_CAUSE_BUFFER_SIZE> buffer) {
   // Zephyr doesn't have detailed wakeup cause like ESP32
   return "";
 }

esphome/components/esp32/__init__.py

@@ -1442,6 +1442,11 @@ async def to_code(config):
     cg.add_build_flag("-DUSE_ESP32")
     cg.add_define("USE_NATIVE_64BIT_TIME")
     cg.add_build_flag("-Wl,-z,noexecstack")
+    # Arduino already wraps esp_panic_handler for its own backtrace handler,
+    # so only add our wrap when using ESP-IDF framework to avoid linker conflicts.
+    if conf[CONF_TYPE] == FRAMEWORK_ESP_IDF:
+        cg.add_build_flag("-Wl,--wrap=esp_panic_handler")
+        cg.add_define("USE_ESP32_CRASH_HANDLER")
     cg.add_define("ESPHOME_BOARD", config[CONF_BOARD])
     variant = config[CONF_VARIANT]
     cg.add_build_flag(f"-DUSE_ESP32_VARIANT_{variant}")

esphome/components/esp32/core.cpp

@@ -1,6 +1,7 @@
 #ifdef USE_ESP32
 
 #include "esphome/core/defines.h"
+#include "crash_handler.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "preferences.h"
@@ -36,6 +37,11 @@ void arch_restart() {
 }
 
 void arch_init() {
+#ifdef USE_ESP32_CRASH_HANDLER
+  // Read crash data from previous boot before anything else
+  esp32::crash_handler_read_and_clear();
+#endif
+
   // Enable the task watchdog only on the loop task (from which we're currently running)
   esp_task_wdt_add(nullptr);
 

esphome/components/esp32/crash_handler.cpp

@@ -0,0 +1,355 @@
+#ifdef USE_ESP32
+
+#include "esphome/core/defines.h"
+#ifdef USE_ESP32_CRASH_HANDLER
+
+#include "crash_handler.h"
+#include "esphome/core/log.h"
+
+#include <cinttypes>
+#include <cstring>
+#include <esp_attr.h>
+#include <esp_private/panic_internal.h>
+#include <soc/soc.h>
+
+#if CONFIG_IDF_TARGET_ARCH_XTENSA
+#include <esp_cpu_utils.h>
+#include <esp_debug_helpers.h>
+#include <xtensa_context.h>
+#elif CONFIG_IDF_TARGET_ARCH_RISCV
+#include <riscv/rvruntime-frames.h>
+#endif
+
+static constexpr uint32_t CRASH_MAGIC = 0xDEADBEEF;
+static constexpr size_t MAX_BACKTRACE = 16;
+
+// Check if an address looks like code (flash-mapped or IRAM).
+// Must be safe to call from panic context (no flash access needed).
+static inline bool IRAM_ATTR is_code_addr(uint32_t addr) {
+  return (addr >= SOC_IROM_LOW && addr < SOC_IROM_HIGH) || (addr >= SOC_IRAM_LOW && addr < SOC_IRAM_HIGH);
+}
+
+#if CONFIG_IDF_TARGET_ARCH_RISCV
+// Check if a code address is a real return address by verifying the preceding
+// instruction is a JAL or JALR with rd=ra (x1). Called at log time (not during
+// panic) so flash cache is available and both IRAM and IROM are safely readable.
+static inline bool is_return_addr(uint32_t addr) {
+  if (!is_code_addr(addr) || addr < 4)
+    return false;
+  // A return address on the stack points to the instruction after a call.
+  // Check for 4-byte JAL/JALR call instruction before this address.
+  // Use memcpy for alignment safety — RISC-V C extension means code addresses
+  // are only 2-byte aligned, so addr-4 may not be 4-byte aligned.
+  uint32_t inst;
+  memcpy(&inst, (const void *) (addr - 4), sizeof(inst));
+  // RISC-V instruction encoding: bits [6:0] = opcode, bits [11:7] = rd
+  uint32_t opcode = inst & 0x7f;  // Extract 7-bit opcode
+  uint32_t rd = inst & 0xf80;     // Extract rd field (bits 11:7)
+  // Match JAL (0x6f) or JALR (0x67) with rd=ra (x1, encoded as 0x80 = 1<<7)
+  if ((opcode == 0x6f || opcode == 0x67) && rd == 0x80)
+    return true;
+  // Check for 2-byte compressed c.jalr before this address (C extension).
+  // c.jalr saves to ra implicitly: funct4=1001, rs1!=0, rs2=0, op=10
+  if (addr >= 2) {
+    uint16_t c_inst = *(uint16_t *) (addr - 2);
+    if ((c_inst & 0xf07f) == 0x9002 && (c_inst & 0x0f80) != 0)
+      return true;
+  }
+  return false;
+}
+#endif
+
+// Raw crash data written by the panic handler wrapper.
+// Lives in .noinit so it survives software reset but contains garbage after power cycle.
+// Validated by magic marker. Static linkage since it's only used within this file.
+// Version field is first so future firmware can always identify the struct layout.
+// Magic is second to validate the data. Remaining fields can change between versions.
+// Version is uint32_t because it would be padded to 4 bytes anyway before the next
+// uint32_t field, so we use the full width rather than wasting 3 bytes of padding.
+static constexpr uint32_t CRASH_DATA_VERSION = 1;
+struct RawCrashData {
+  uint32_t version;
+  uint32_t magic;
+  uint32_t pc;
+  uint8_t backtrace_count;
+  uint8_t reg_frame_count;  // Number of entries from registers (not stack-scanned)
+  uint8_t exception;        // panic_exception_t enum (FAULT/ABORT/IWDT/TWDT/DEBUG)
+  uint8_t pseudo_excause;   // Whether cause is a pseudo exception (Xtensa SoC-level panic)
+  uint32_t backtrace[MAX_BACKTRACE];
+  uint32_t cause;  // Architecture-specific: exccause (Xtensa) or mcause (RISC-V)
+};
+static RawCrashData __attribute__((section(".noinit")))
+s_raw_crash_data;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
+// Whether crash data was found and validated this boot.
+static bool s_crash_data_valid = false;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
+namespace esphome::esp32 {
+
+static const char *const TAG = "esp32.crash";
+
+void crash_handler_read_and_clear() {
+  if (s_raw_crash_data.magic == CRASH_MAGIC && s_raw_crash_data.version == CRASH_DATA_VERSION) {
+    s_crash_data_valid = true;
+    // Clamp counts to prevent out-of-bounds reads from corrupt .noinit data
+    if (s_raw_crash_data.backtrace_count > MAX_BACKTRACE)
+      s_raw_crash_data.backtrace_count = MAX_BACKTRACE;
+    if (s_raw_crash_data.reg_frame_count > s_raw_crash_data.backtrace_count)
+      s_raw_crash_data.reg_frame_count = s_raw_crash_data.backtrace_count;
+    if (s_raw_crash_data.exception > 4)  // panic_exception_t max value
+      s_raw_crash_data.exception = 4;    // Default to PANIC_EXCEPTION_FAULT
+    if (s_raw_crash_data.pseudo_excause > 1)
+      s_raw_crash_data.pseudo_excause = 0;
+  }
+  // Clear magic regardless so we don't re-report on next normal reboot
+  s_raw_crash_data.magic = 0;
+}
+
+bool crash_handler_has_data() { return s_crash_data_valid; }
+
+// Look up the exception cause as a human-readable string.
+// Tables mirror ESP-IDF's panic_arch_fill_info() which uses local static arrays
+// not exposed via any public API.
+static const char *get_exception_reason() {
+#if CONFIG_IDF_TARGET_ARCH_XTENSA
+  if (s_raw_crash_data.pseudo_excause) {
+    // SoC-level panic: watchdog, cache error, etc.
+    // Keep in sync with ESP-IDF's PANIC_RSN_* defines
+    static const char *const PSEUDO_REASON[] = {
+        "Unknown reason",                 // 0
+        "Unhandled debug exception",      // 1
+        "Double exception",               // 2
+        "Unhandled kernel exception",     // 3
+        "Coprocessor exception",          // 4
+        "Interrupt wdt timeout on CPU0",  // 5
+        "Interrupt wdt timeout on CPU1",  // 6
+        "Cache error",                    // 7
+    };
+    uint32_t cause = s_raw_crash_data.cause;
+    if (cause < sizeof(PSEUDO_REASON) / sizeof(PSEUDO_REASON[0]))
+      return PSEUDO_REASON[cause];
+    return PSEUDO_REASON[0];
+  }
+  // Real Xtensa exception
+  static const char *const REASON[] = {
+      "IllegalInstruction",
+      "Syscall",
+      "InstructionFetchError",
+      "LoadStoreError",
+      "Level1Interrupt",
+      "Alloca",
+      "IntegerDivideByZero",
+      "PCValue",
+      "Privileged",
+      "LoadStoreAlignment",
+      nullptr,
+      nullptr,
+      "InstrPDAddrError",
+      "LoadStorePIFDataError",
+      "InstrPIFAddrError",
+      "LoadStorePIFAddrError",
+      "InstTLBMiss",
+      "InstTLBMultiHit",
+      "InstFetchPrivilege",
+      nullptr,
+      "InstrFetchProhibited",
+      nullptr,
+      nullptr,
+      nullptr,
+      "LoadStoreTLBMiss",
+      "LoadStoreTLBMultihit",
+      "LoadStorePrivilege",
+      nullptr,
+      "LoadProhibited",
+      "StoreProhibited",
+  };
+  uint32_t cause = s_raw_crash_data.cause;
+  if (cause < sizeof(REASON) / sizeof(REASON[0]) && REASON[cause] != nullptr)
+    return REASON[cause];
+#elif CONFIG_IDF_TARGET_ARCH_RISCV
+  // For SoC-level panics (watchdog, cache error), mcause holds IDF-internal
+  // interrupt numbers, not standard RISC-V cause codes. The exception type
+  // field already identifies these, so just return null to use the type name.
+  if (s_raw_crash_data.pseudo_excause)
+    return nullptr;
+  static const char *const REASON[] = {
+      "Instruction address misaligned",
+      "Instruction access fault",
+      "Illegal instruction",
+      "Breakpoint",
+      "Load address misaligned",
+      "Load access fault",
+      "Store address misaligned",
+      "Store access fault",
+      "Environment call from U-mode",
+      "Environment call from S-mode",
+      nullptr,
+      "Environment call from M-mode",
+      "Instruction page fault",
+      "Load page fault",
+      nullptr,
+      "Store page fault",
+  };
+  uint32_t cause = s_raw_crash_data.cause;
+  if (cause < sizeof(REASON) / sizeof(REASON[0]) && REASON[cause] != nullptr)
+    return REASON[cause];
+#endif
+  return "Unknown";
+}
+
+// Exception type names matching panic_exception_t enum
+static const char *get_exception_type() {
+  static const char *const TYPES[] = {
+      "Debug exception",  // PANIC_EXCEPTION_DEBUG
+      "Interrupt wdt",    // PANIC_EXCEPTION_IWDT
+      "Task wdt",         // PANIC_EXCEPTION_TWDT
+      "Abort",            // PANIC_EXCEPTION_ABORT
+      "Fault",            // PANIC_EXCEPTION_FAULT
+  };
+  uint8_t exc = s_raw_crash_data.exception;
+  if (exc < sizeof(TYPES) / sizeof(TYPES[0]))
+    return TYPES[exc];
+  return "Unknown";
+}
+
+// Intentionally uses separate ESP_LOGE calls per line instead of combining into
+// one multi-line log message. This ensures each address appears as its own line
+// on the serial console, making it possible to see partial output if the device
+// crashes again during boot, and allowing the CLI's process_stacktrace to match
+// and decode each address individually.
+void crash_handler_log() {
+  if (!s_crash_data_valid)
+    return;
+
+  ESP_LOGE(TAG, "*** CRASH DETECTED ON PREVIOUS BOOT ***");
+  const char *reason = get_exception_reason();
+  if (reason != nullptr) {
+    ESP_LOGE(TAG, "  Reason: %s - %s", get_exception_type(), reason);
+  } else {
+    ESP_LOGE(TAG, "  Reason: %s", get_exception_type());
+  }
+  ESP_LOGE(TAG, "  PC:  0x%08" PRIX32 "  (fault location)", s_raw_crash_data.pc);
+  uint8_t bt_num = 0;
+  for (uint8_t i = 0; i < s_raw_crash_data.backtrace_count; i++) {
+    uint32_t addr = s_raw_crash_data.backtrace[i];
+#if CONFIG_IDF_TARGET_ARCH_RISCV
+    // Register-sourced entries (MEPC/RA) are trusted; only filter stack-scanned ones.
+    if (i >= s_raw_crash_data.reg_frame_count && !is_return_addr(addr))
+      continue;
+#endif
+#if CONFIG_IDF_TARGET_ARCH_RISCV
+    const char *source = (i < s_raw_crash_data.reg_frame_count) ? "backtrace" : "stack scan";
+#else
+    const char *source = "backtrace";
+#endif
+    ESP_LOGE(TAG, "  BT%d: 0x%08" PRIX32 "  (%s)", bt_num++, addr, source);
+  }
+  // Build addr2line hint with all captured addresses for easy copy-paste
+  char hint[256];
+  int pos = snprintf(hint, sizeof(hint), "Use: addr2line -pfiaC -e firmware.elf 0x%08" PRIX32, s_raw_crash_data.pc);
+  for (uint8_t i = 0; i < s_raw_crash_data.backtrace_count && pos < (int) sizeof(hint) - 12; i++) {
+    uint32_t addr = s_raw_crash_data.backtrace[i];
+#if CONFIG_IDF_TARGET_ARCH_RISCV
+    if (i >= s_raw_crash_data.reg_frame_count && !is_return_addr(addr))
+      continue;
+#endif
+    pos += snprintf(hint + pos, sizeof(hint) - pos, " 0x%08" PRIX32, addr);
+  }
+  ESP_LOGE(TAG, "%s", hint);
+}
+
+}  // namespace esphome::esp32
+
+// --- Panic handler wrapper ---
+// Intercepts esp_panic_handler() via --wrap linker flag to capture crash data
+// into NOINIT memory before the normal panic handler runs.
+//
+extern "C" {
+// NOLINTBEGIN(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp,readability-identifier-naming)
+// Names are mandated by the --wrap linker mechanism
+extern void __real_esp_panic_handler(panic_info_t *info);
+
+void IRAM_ATTR __wrap_esp_panic_handler(panic_info_t *info) {
+  // Save the faulting PC and exception info
+  s_raw_crash_data.pc = (uint32_t) info->addr;
+  s_raw_crash_data.backtrace_count = 0;
+  s_raw_crash_data.reg_frame_count = 0;
+  s_raw_crash_data.exception = (uint8_t) info->exception;
+  s_raw_crash_data.pseudo_excause = info->pseudo_excause ? 1 : 0;
+
+#if CONFIG_IDF_TARGET_ARCH_XTENSA
+  // Xtensa: walk the backtrace using the public API
+  if (info->frame != nullptr) {
+    auto *xt_frame = (XtExcFrame *) info->frame;
+    s_raw_crash_data.cause = xt_frame->exccause;
+    esp_backtrace_frame_t bt_frame = {
+        .pc = (uint32_t) xt_frame->pc,
+        .sp = (uint32_t) xt_frame->a1,
+        .next_pc = (uint32_t) xt_frame->a0,
+        .exc_frame = xt_frame,
+    };
+
+    uint8_t count = 0;
+    // First frame PC
+    uint32_t first_pc = esp_cpu_process_stack_pc(bt_frame.pc);
+    if (is_code_addr(first_pc)) {
+      s_raw_crash_data.backtrace[count++] = first_pc;
+    }
+    // Walk remaining frames
+    while (count < MAX_BACKTRACE && bt_frame.next_pc != 0) {
+      if (!esp_backtrace_get_next_frame(&bt_frame)) {
+        break;
+      }
+      uint32_t pc = esp_cpu_process_stack_pc(bt_frame.pc);
+      if (is_code_addr(pc)) {
+        s_raw_crash_data.backtrace[count++] = pc;
+      }
+    }
+    s_raw_crash_data.backtrace_count = count;
+  }
+
+#elif CONFIG_IDF_TARGET_ARCH_RISCV
+  // RISC-V: capture MEPC + RA, then scan stack for code addresses
+  if (info->frame != nullptr) {
+    auto *rv_frame = (RvExcFrame *) info->frame;
+    s_raw_crash_data.cause = rv_frame->mcause;
+    uint8_t count = 0;
+
+    // Save MEPC (fault PC) and RA (return address)
+    if (is_code_addr(rv_frame->mepc)) {
+      s_raw_crash_data.backtrace[count++] = rv_frame->mepc;
+    }
+    if (is_code_addr(rv_frame->ra) && rv_frame->ra != rv_frame->mepc) {
+      s_raw_crash_data.backtrace[count++] = rv_frame->ra;
+    }
+
+    // Track how many entries came from registers (MEPC/RA) so we can
+    // skip return-address validation for them at log time.
+    s_raw_crash_data.reg_frame_count = count;
+
+    // Scan stack for code addresses — captures broadly during panic,
+    // filtered by is_return_addr() at log time when flash is accessible.
+    auto *scan_start = (uint32_t *) rv_frame->sp;
+    for (uint32_t i = 0; i < 64 && count < MAX_BACKTRACE; i++) {
+      uint32_t val = scan_start[i];
+      if (is_code_addr(val) && val != rv_frame->mepc && val != rv_frame->ra) {
+        s_raw_crash_data.backtrace[count++] = val;
+      }
+    }
+    s_raw_crash_data.backtrace_count = count;
+  }
+#endif
+
+  // Write version and magic last — ensures all data is written before we mark it valid
+  s_raw_crash_data.version = CRASH_DATA_VERSION;
+  s_raw_crash_data.magic = CRASH_MAGIC;
+
+  // Call the real panic handler (prints to UART, does core dump, reboots, etc.)
+  __real_esp_panic_handler(info);
+}
+
+// NOLINTEND(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp,readability-identifier-naming)
+}  // extern "C"
+
+#endif  // USE_ESP32_CRASH_HANDLER
+#endif  // USE_ESP32

esphome/components/esp32/crash_handler.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#ifdef USE_ESP32_CRASH_HANDLER
+
+namespace esphome::esp32 {
+
+/// Read crash data from NOINIT memory and clear the magic marker.
+void crash_handler_read_and_clear();
+
+/// Log crash data if a crash was detected on previous boot.
+void crash_handler_log();
+
+/// Returns true if crash data was found this boot.
+bool crash_handler_has_data();
+
+}  // namespace esphome::esp32
+
+#endif  // USE_ESP32_CRASH_HANDLER

esphome/components/esp32_ble_client/ble_client_base.cpp

@@ -27,6 +27,7 @@ static constexpr uint16_t MEDIUM_CONN_TIMEOUT = 800;  // 800 * 10ms = 8s
 static constexpr uint16_t FAST_MIN_CONN_INTERVAL = 0x06;  // 6 * 1.25ms = 7.5ms (BLE minimum)
 static constexpr uint16_t FAST_MAX_CONN_INTERVAL = 0x06;  // 6 * 1.25ms = 7.5ms
 static constexpr uint16_t FAST_CONN_TIMEOUT = 1000;       // 1000 * 10ms = 10s
+static constexpr uint32_t DISCONNECTING_TIMEOUT = 10000;  // 10s
 static const esp_bt_uuid_t NOTIFY_DESC_UUID = {
     .len = ESP_UUID_LEN_16,
     .uuid =
@@ -62,6 +63,15 @@ void BLEClientBase::loop() {
   // will enable it again when a connection is needed.
   else if (this->state() == espbt::ClientState::IDLE) {
     this->disable_loop();
+  } else if (this->state() == espbt::ClientState::DISCONNECTING &&
+             (millis() - this->disconnecting_started_) > DISCONNECTING_TIMEOUT) {
+    ESP_LOGE(TAG, "[%d] [%s] Timeout waiting for CLOSE_EVT after disconnect, forcing IDLE", this->connection_index_,
+             this->address_str_);
+    // release_services() must be called before set_idle_() — if we entered DISCONNECTING
+    // via unconditional_disconnect() (which doesn't call release_services()), and ESP-IDF
+    // never delivered CLOSE_EVT/DISCONNECT_EVT, services would leak without this call.
+    this->release_services();
+    this->set_idle_();
   }
 }
 
@@ -101,12 +111,16 @@ bool BLEClientBase::parse_device(const espbt::ESPBTDevice &device) {
 #endif
 
 void BLEClientBase::connect() {
-  // Prevent duplicate connection attempts
+  // Prevent duplicate connection attempts or connecting while still disconnecting
   if (this->state() == espbt::ClientState::CONNECTING || this->state() == espbt::ClientState::CONNECTED ||
       this->state() == espbt::ClientState::ESTABLISHED) {
     ESP_LOGW(TAG, "[%d] [%s] Connection already in progress, state=%s", this->connection_index_, this->address_str_,
              espbt::client_state_to_string(this->state()));
     return;
+  } else if (this->state() == espbt::ClientState::DISCONNECTING) {
+    ESP_LOGW(TAG, "[%d] [%s] Cannot connect, still waiting for CLOSE_EVT to complete disconnect",
+             this->connection_index_, this->address_str_);
+    return;
   }
   ESP_LOGI(TAG, "[%d] [%s] 0x%02x Connecting", this->connection_index_, this->address_str_, this->remote_addr_type_);
   this->paired_ = false;
@@ -174,7 +188,7 @@ void BLEClientBase::unconditional_disconnect() {
     this->set_address(0);
     this->set_state(espbt::ClientState::IDLE);
   } else {
-    this->set_state(espbt::ClientState::DISCONNECTING);
+    this->set_disconnecting_();
   }
 }
 
@@ -220,6 +234,7 @@ void BLEClientBase::log_connection_params_(const char *param_type) {
 void BLEClientBase::handle_connection_result_(esp_err_t ret) {
   if (ret) {
     this->log_gattc_warning_("esp_ble_gattc_open", ret);
+    // Don't use set_idle_() here — CONNECT_EVT never fired so conn_id_ is still UNSET_CONN_ID.
     this->set_state(espbt::ClientState::IDLE);
   }
 }
@@ -311,15 +326,16 @@ bool BLEClientBase::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_
       }
       if (param->open.status != ESP_GATT_OK && param->open.status != ESP_GATT_ALREADY_OPEN) {
         this->log_gattc_warning_("Connection open", param->open.status);
-        this->set_state(espbt::ClientState::IDLE);
+        // Connection was never established so CLOSE_EVT may not follow
+        this->set_idle_();
         break;
       }
       if (this->want_disconnect_) {
         // Disconnect was requested after connecting started,
         // but before the connection was established. Now that we have
         // this->conn_id_ set, we can disconnect it.
+        // Don't reset conn_id_ here — CLOSE_EVT needs it to match and call set_idle_().
         this->unconditional_disconnect();
-        this->conn_id_ = UNSET_CONN_ID;
         break;
       }
       // MTU negotiation already started in ESP_GATTC_CONNECT_EVT
@@ -363,8 +379,22 @@ bool BLEClientBase::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_
         ESP_LOGD(TAG, "[%d] [%s] ESP_GATTC_DISCONNECT_EVT, reason 0x%02x", this->connection_index_, this->address_str_,
                  param->disconnect.reason);
       }
+      // For active disconnects (esp_ble_gattc_close), CLOSE_EVT arrives before
+      // DISCONNECT_EVT. If CLOSE_EVT already transitioned us to IDLE, don't go
+      // backwards to DISCONNECTING — the connection is already fully cleaned up.
+      if (this->state() == espbt::ClientState::IDLE) {
+        this->log_event_("DISCONNECT_EVT after CLOSE_EVT, already IDLE");
+        break;
+      }
+      // For passive disconnects (remote device disconnected or link lost),
+      // DISCONNECT_EVT arrives first. Don't transition to IDLE yet — wait for
+      // CLOSE_EVT to ensure the controller has fully freed resources (L2CAP
+      // channels, ATT resources, HCI connection handle). Transitioning to IDLE
+      // here would allow reconnection before cleanup is complete, causing the
+      // controller to reject the new connection (status=133) or crash with
+      // ASSERT_PARAM in lld_evt.c.
       this->release_services();
-      this->set_state(espbt::ClientState::IDLE);
+      this->set_disconnecting_();
       break;
     }
 
@@ -387,8 +417,7 @@ bool BLEClientBase::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_
         return false;
       this->log_gattc_lifecycle_event_("CLOSE");
       this->release_services();
-      this->set_state(espbt::ClientState::IDLE);
-      this->conn_id_ = UNSET_CONN_ID;
+      this->set_idle_();
       break;
     }
     case ESP_GATTC_SEARCH_RES_EVT: {

esphome/components/esp32_ble_client/ble_client_base.h

@@ -113,11 +113,14 @@ class BLEClientBase : public espbt::ESPBTClient, public Component {
   char address_str_[MAC_ADDRESS_PRETTY_BUFFER_SIZE]{};
   esp_bd_addr_t remote_bda_;  // 6 bytes
 
-  // Group 5: 2-byte types
+  // Group 5: 4-byte types
+  uint32_t disconnecting_started_{0};
+
+  // Group 6: 2-byte types
   uint16_t conn_id_{UNSET_CONN_ID};
   uint16_t mtu_{23};
 
-  // Group 6: 1-byte types and small enums
+  // Group 7: 1-byte types and small enums
   esp_ble_addr_type_t remote_addr_type_{BLE_ADDR_TYPE_PUBLIC};
   espbt::ConnectionType connection_type_{espbt::ConnectionType::V1};
   uint8_t connection_index_;
@@ -137,6 +140,16 @@ class BLEClientBase : public espbt::ESPBTClient, public Component {
   void log_gattc_warning_(const char *operation, esp_err_t err);
   void log_connection_params_(const char *param_type);
   void handle_connection_result_(esp_err_t ret);
+  /// Transition to IDLE and reset conn_id — call when the connection is fully dead.
+  void set_idle_() {
+    this->set_state(espbt::ClientState::IDLE);
+    this->conn_id_ = UNSET_CONN_ID;
+  }
+  /// Transition to DISCONNECTING and start the safety timeout.
+  void set_disconnecting_() {
+    this->disconnecting_started_ = millis();
+    this->set_state(espbt::ClientState::DISCONNECTING);
+  }
   // Compact error logging helpers to reduce flash usage
   void log_error_(const char *message);
   void log_error_(const char *message, int code);

esphome/components/esp32_hosted/__init__.py

@@ -105,7 +105,7 @@ async def to_code(config):
     if framework_ver >= cv.Version(5, 5, 0):
         esp32.add_idf_component(name="espressif/esp_wifi_remote", ref="1.4.0")
         esp32.add_idf_component(name="espressif/eppp_link", ref="1.1.4")
-        esp32.add_idf_component(name="espressif/esp_hosted", ref="2.12.0")
+        esp32.add_idf_component(name="espressif/esp_hosted", ref="2.12.1")
     else:
         esp32.add_idf_component(name="espressif/esp_wifi_remote", ref="0.13.0")
         esp32.add_idf_component(name="espressif/eppp_link", ref="0.2.0")

esphome/components/esp8266/helpers.cpp

@@ -22,9 +22,7 @@ void Mutex::unlock() {}
 IRAM_ATTR InterruptLock::InterruptLock() { state_ = xt_rsil(15); }
 IRAM_ATTR InterruptLock::~InterruptLock() { xt_wsr_ps(state_); }
 
-// ESP8266 doesn't support lwIP core locking, so this is a no-op
-LwIPLock::LwIPLock() {}
-LwIPLock::~LwIPLock() {}
+// ESP8266 LwIPLock is defined inline as a no-op in helpers.h
 
 void get_mac_address_raw(uint8_t *mac) {  // NOLINT(readability-non-const-parameter)
   wifi_get_macaddr(STATION_IF, mac);

esphome/components/esphome/ota/ota_esphome.cpp

@@ -18,6 +18,7 @@
 
 #include <cerrno>
 #include <cstdio>
+#include <sys/time.h>
 
 namespace esphome {
 
@@ -238,6 +239,31 @@ void ESPHomeOTAComponent::handle_data_() {
   /// and reboots on success.
   ///
   /// Authentication has already been handled in the non-blocking states AUTH_SEND/AUTH_READ.
+  ///
+  /// Socket I/O strategy:
+  ///
+  /// Before this function, the handshake states use non-blocking I/O:
+  ///   read()/write() return immediately with EWOULDBLOCK if no data
+  ///   loop() retries on next iteration (~16ms), no delay needed
+  ///
+  /// This function switches to blocking mode with SO_RCVTIMEO/SO_SNDTIMEO:
+  ///
+  ///   Path          | Wait mechanism         | WDT strategy
+  ///   --------------|------------------------|---------------------------
+  ///   Main read     | SO_RCVTIMEO (2s block) | feed_wdt() only, no delay
+  ///   readall_()    | SO_RCVTIMEO (2s block) | feed_wdt() + delay(0)
+  ///   writeall_()   | SO_SNDTIMEO (2s block) | feed_wdt() + delay(1)
+  ///
+  /// readall_() uses delay(0) because SO_RCVTIMEO already waited — just yield.
+  /// writeall_() uses delay(1) because on raw TCP (ESP8266, RP2040) writes
+  /// never block (tcp_write returns immediately), so delay(1) prevents spinning.
+  ///
+  /// Platform details:
+  ///   BSD sockets (ESP32):     setblocking(true) makes read/write block
+  ///   lwip sockets (LT):      setblocking(true) makes read/write block
+  ///   Raw TCP (8266, RP2040):  setblocking is no-op; SO_RCVTIMEO uses
+  ///                            socket_delay()/socket_wake() in read();
+  ///                            write() always returns immediately
   ota::OTAResponseTypes error_code = ota::OTA_RESPONSE_ERROR_UNKNOWN;
   bool update_started = false;
   size_t total = 0;
@@ -249,6 +275,14 @@ void ESPHomeOTAComponent::handle_data_() {
   size_t size_acknowledged = 0;
 #endif
 
+  // Set socket timeouts and blocking mode (see strategy table above)
+  struct timeval tv;
+  tv.tv_sec = 2;
+  tv.tv_usec = 0;
+  this->client_->setsockopt(SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
+  this->client_->setsockopt(SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+  this->client_->setblocking(true);
+
   // Acknowledge auth OK - 1 byte
   this->write_byte_(ota::OTA_RESPONSE_AUTH_OK);
 
@@ -299,7 +333,8 @@ void ESPHomeOTAComponent::handle_data_() {
     ssize_t read = this->client_->read(buf, requested);
     if (read == -1) {
       if (this->would_block_(errno)) {
-        this->yield_and_feed_watchdog_();
+        // read() already waited up to SO_RCVTIMEO for data, just feed WDT
+        App.feed_wdt();
         continue;
       }
       ESP_LOGW(TAG, "Read err %d", errno);
@@ -401,7 +436,9 @@ bool ESPHomeOTAComponent::readall_(uint8_t *buf, size_t len) {
     } else {
       at += read;
     }
-    this->yield_and_feed_watchdog_();
+    // read() already waited via SO_RCVTIMEO, just yield without 1ms stall
+    App.feed_wdt();
+    delay(0);
   }
 
   return true;
@@ -422,10 +459,13 @@ bool ESPHomeOTAComponent::writeall_(const uint8_t *buf, size_t len) {
         ESP_LOGW(TAG, "Write err %zu bytes, errno %d", len, errno);
         return false;
       }
+      // EWOULDBLOCK: on raw TCP writes never block, delay(1) prevents spinning
+      this->yield_and_feed_watchdog_();
     } else {
       at += written;
+      // write() may block up to SO_SNDTIMEO on BSD/lwip sockets, feed WDT
+      App.feed_wdt();
     }
-    this->yield_and_feed_watchdog_();
   }
   return true;
 }

esphome/components/ethernet/ethernet_component.cpp

@@ -21,22 +21,6 @@
 
 namespace esphome::ethernet {
 
-#if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(5, 4, 2)
-// work around IDF compile issue on P4 https://github.com/espressif/esp-idf/pull/15637
-#ifdef USE_ESP32_VARIANT_ESP32P4
-#undef ETH_ESP32_EMAC_DEFAULT_CONFIG
-#define ETH_ESP32_EMAC_DEFAULT_CONFIG() \
-  { \
-    .smi_gpio = {.mdc_num = 31, .mdio_num = 52}, .interface = EMAC_DATA_INTERFACE_RMII, \
-    .clock_config = {.rmii = {.clock_mode = EMAC_CLK_EXT_IN, .clock_gpio = (emac_rmii_clock_gpio_t) 50}}, \
-    .dma_burst_len = ETH_DMA_BURST_LEN_32, .intr_priority = 0, \
-    .emac_dataif_gpio = \
-        {.rmii = {.tx_en_num = 49, .txd0_num = 34, .txd1_num = 35, .crs_dv_num = 28, .rxd0_num = 29, .rxd1_num = 30}}, \
-    .clock_config_out_in = {.rmii = {.clock_mode = EMAC_CLK_EXT_IN, .clock_gpio = (emac_rmii_clock_gpio_t) -1}}, \
-  }
-#endif
-#endif
-
 static const char *const TAG = "ethernet";
 
 // PHY register size for hex logging
@@ -162,7 +146,7 @@ void EthernetComponent::setup() {
   phy_config.phy_addr = this->phy_addr_;
   phy_config.reset_gpio_num = this->power_pin_;
 
-  eth_esp32_emac_config_t esp32_emac_config = ETH_ESP32_EMAC_DEFAULT_CONFIG();
+  eth_esp32_emac_config_t esp32_emac_config = eth_esp32_emac_default_config();
 #if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0)
   esp32_emac_config.smi_gpio.mdc_num = this->mdc_pin_;
   esp32_emac_config.smi_gpio.mdio_num = this->mdio_pin_;

esphome/components/ethernet/ethernet_component.h

@@ -11,10 +11,15 @@
 
 #include "esp_eth.h"
 #include "esp_eth_mac.h"
+#include "esp_eth_mac_esp.h"
 #include "esp_netif.h"
 #include "esp_mac.h"
 #include "esp_idf_version.h"
 
+#if CONFIG_ETH_USE_ESP32_EMAC
+extern "C" eth_esp32_emac_config_t eth_esp32_emac_default_config(void);
+#endif
+
 namespace esphome::ethernet {
 
 #ifdef USE_ETHERNET_IP_STATE_LISTENERS

esphome/components/ethernet/ethernet_helpers.c

@@ -0,0 +1,10 @@
+#include "esp_eth_mac_esp.h"
+
+// ETH_ESP32_EMAC_DEFAULT_CONFIG() uses out-of-order designated initializers
+// which are valid in C but not in C++. This wrapper allows C++ code to get
+// the default config without replicating the macro's contents.
+#if CONFIG_ETH_USE_ESP32_EMAC
+eth_esp32_emac_config_t eth_esp32_emac_default_config(void) {
+  return (eth_esp32_emac_config_t) ETH_ESP32_EMAC_DEFAULT_CONFIG();
+}
+#endif

esphome/components/i2c/__init__.py

@@ -93,11 +93,31 @@ def _bus_declare_type(value):
     raise NotImplementedError
 
 
+def _rp2040_i2c_controller(pin):
+    """Return the I2C controller number (0 or 1) for a given RP2040/RP2350 GPIO pin.
+
+    See RP2040 datasheet Table 2 (section 1.4.3, "GPIO Functions"):
+    https://datasheets.raspberrypi.com/rp2040/rp2040-datasheet.pdf
+    See RP2350 datasheet Table 7 (section 9.4, "Function Select"):
+    https://datasheets.raspberrypi.com/rp2350/rp2350-datasheet.pdf
+    """
+    return (pin // 2) % 2
+
+
 def validate_config(config):
     if CORE.is_esp32:
         return cv.require_framework_version(
             esp_idf=cv.Version(5, 4, 2), esp32_arduino=cv.Version(3, 2, 1)
         )(config)
+    if CORE.is_rp2040:
+        sda_controller = _rp2040_i2c_controller(config[CONF_SDA])
+        scl_controller = _rp2040_i2c_controller(config[CONF_SCL])
+        if sda_controller != scl_controller:
+            raise cv.Invalid(
+                f"SDA pin GPIO{config[CONF_SDA]} is on I2C{sda_controller} but "
+                f"SCL pin GPIO{config[CONF_SCL]} is on I2C{scl_controller}. "
+                f"Both pins must be on the same I2C controller."
+            )
     return config
 
 
@@ -146,6 +166,23 @@ def _final_validate(config):
     full_config = fv.full_config.get()[CONF_I2C]
     if CORE.using_zephyr and len(full_config) > 1:
         raise cv.Invalid("Second i2c is not implemented on Zephyr yet")
+    if CORE.is_rp2040:
+        if len(full_config) > 2:
+            raise cv.Invalid(
+                "The maximum number of I2C interfaces for RP2040/RP2350 is 2"
+            )
+        if len(full_config) > 1:
+            controllers = [
+                _rp2040_i2c_controller(conf[CONF_SDA]) for conf in full_config
+            ]
+            if len(set(controllers)) != len(controllers):
+                raise cv.Invalid(
+                    "Multiple I2C buses are configured to use the same I2C controller. "
+                    "Each bus must use pins on a different controller. "
+                    "The I2C controller is determined by (gpio / 2) % 2: "
+                    "even pin pairs (0-1, 4-5, 8-9, ...) use I2C0, "
+                    "odd pin pairs (2-3, 6-7, 10-11, ...) use I2C1."
+                )
     if CORE.is_esp32 and get_esp32_variant() in ESP32_I2C_CAPABILITIES:
         variant = get_esp32_variant()
         max_num = ESP32_I2C_CAPABILITIES[variant]["NUM"]

esphome/components/i2c/i2c_bus_arduino.cpp

@@ -20,12 +20,14 @@ void ArduinoI2CBus::setup() {
 #if defined(USE_ESP8266)
   wire_ = new TwoWire();  // NOLINT(cppcoreguidelines-owning-memory)
 #elif defined(USE_RP2040)
-  static bool first = true;
-  if (first) {
+  // Select Wire instance based on pin assignment, not definition order.
+  // I2C controller = (gpio / 2) % 2: even pairs (0-1,4-5,...) → I2C0, odd pairs (2-3,6-7,...) → I2C1
+  // RP2040 datasheet Table 2 (section 1.4.3): https://datasheets.raspberrypi.com/rp2040/rp2040-datasheet.pdf
+  // RP2350 datasheet Table 7 (section 9.4): https://datasheets.raspberrypi.com/rp2350/rp2350-datasheet.pdf
+  if ((this->sda_pin_ / 2) % 2 == 0) {
     wire_ = &Wire;
-    first = false;
   } else {
-    wire_ = &Wire1;  // NOLINT(cppcoreguidelines-owning-memory)
+    wire_ = &Wire1;
   }
 #endif
 

esphome/components/ledc/ledc_output.cpp

@@ -5,6 +5,10 @@
 
 #include <driver/ledc.h>
 #include <cinttypes>
+#include <esp_private/periph_ctrl.h>
+#if !defined(SOC_LEDC_SUPPORT_FADE_STOP)
+#include <hal/ledc_ll.h>
+#endif
 
 #define CLOCK_FREQUENCY 80e6f
 
@@ -16,10 +20,10 @@
 
 static const uint8_t SETUP_ATTEMPT_COUNT_MAX = 5;
 
-namespace esphome {
-namespace ledc {
+namespace esphome::ledc {
 
 static const char *const TAG = "ledc.output";
+static bool ledc_peripheral_reset_done = false;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
 static const int MAX_RES_BITS = LEDC_TIMER_BIT_MAX - 1;
 #if SOC_LEDC_SUPPORT_HS_MODE
@@ -32,6 +36,28 @@ inline ledc_mode_t get_speed_mode(uint8_t channel) { return channel < 8 ? LEDC_H
 inline ledc_mode_t get_speed_mode(uint8_t) { return LEDC_LOW_SPEED_MODE; }
 #endif
 
+#if !defined(SOC_LEDC_SUPPORT_FADE_STOP)
+// Classic ESP32 (currently the only target without SOC_LEDC_SUPPORT_FADE_STOP) can block in
+// ledc_ll_set_duty_start() while duty_start is set. We check the same conf1.duty_start bit here
+// to defer updates and avoid entering IDF's unbounded wait loop.
+//
+// This intentionally depends on the classic ESP32 LEDC register layout used by IDF's own LL HAL.
+// If another target without SOC_LEDC_SUPPORT_FADE_STOP is introduced, revisit this helper.
+static_assert(
+#if defined(CONFIG_IDF_TARGET_ESP32)
+    true,
+#else
+    false,
+#endif
+    "LEDC duty_start pending check assumes classic ESP32 register layout; "
+    "re-evaluate for this target");
+
+static bool ledc_duty_update_pending(ledc_mode_t speed_mode, ledc_channel_t chan_num) {
+  auto *hw = LEDC_LL_GET_HW();
+  return hw->channel_group[speed_mode].channel[chan_num].conf1.duty_start != 0;
+}
+#endif
+
 float ledc_max_frequency_for_bit_depth(uint8_t bit_depth) {
   return static_cast<float>(CLOCK_FREQUENCY) / static_cast<float>(1 << bit_depth);
 }
@@ -105,21 +131,40 @@ void LEDCOutput::write_state(float state) {
   const uint32_t max_duty = (uint32_t(1) << this->bit_depth_) - 1;
   const float duty_rounded = roundf(state * max_duty);
   auto duty = static_cast<uint32_t>(duty_rounded);
+  if (duty == this->last_duty_) {
+    return;
+  }
+
   ESP_LOGV(TAG, "Setting duty: %" PRIu32 " on channel %u", duty, this->channel_);
   auto speed_mode = get_speed_mode(this->channel_);
   auto chan_num = static_cast<ledc_channel_t>(this->channel_ % 8);
   int hpoint = ledc_angle_to_htop(this->phase_angle_, this->bit_depth_);
   if (duty == max_duty) {
     ledc_stop(speed_mode, chan_num, 1);
+    this->last_duty_ = duty;
   } else if (duty == 0) {
     ledc_stop(speed_mode, chan_num, 0);
+    this->last_duty_ = duty;
   } else {
+#if !defined(SOC_LEDC_SUPPORT_FADE_STOP)
+    if (ledc_duty_update_pending(speed_mode, chan_num)) {
+      ESP_LOGV(TAG, "Skipping LEDC duty update on channel %u while previous duty_start is still set", this->channel_);
+      return;
+    }
+#endif
     ledc_set_duty_with_hpoint(speed_mode, chan_num, duty, hpoint);
     ledc_update_duty(speed_mode, chan_num);
+    this->last_duty_ = duty;
   }
 }
 
 void LEDCOutput::setup() {
+  if (!ledc_peripheral_reset_done) {
+    ESP_LOGV(TAG, "Resetting LEDC peripheral to clear stale state after reboot");
+    periph_module_reset(PERIPH_LEDC_MODULE);
+    ledc_peripheral_reset_done = true;
+  }
+
   auto speed_mode = get_speed_mode(this->channel_);
   auto timer_num = static_cast<ledc_timer_t>((this->channel_ % 8) / 2);
   auto chan_num = static_cast<ledc_channel_t>(this->channel_ % 8);
@@ -207,12 +252,12 @@ void LEDCOutput::update_frequency(float frequency) {
   this->status_clear_error();
 
   // re-apply duty
+  this->last_duty_ = UINT32_MAX;
   this->write_state(this->duty_);
 }
 
 uint8_t next_ledc_channel = 0;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
-}  // namespace ledc
-}  // namespace esphome
+}  // namespace esphome::ledc
 
 #endif

esphome/components/ledc/ledc_output.h

@@ -4,11 +4,11 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/automation.h"
 #include "esphome/components/output/float_output.h"
+#include <cstdint>
 
 #ifdef USE_ESP32
 
-namespace esphome {
-namespace ledc {
+namespace esphome::ledc {
 
 // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
 extern uint8_t next_ledc_channel;
@@ -39,6 +39,7 @@ class LEDCOutput : public output::FloatOutput, public Component {
   float phase_angle_{0.0f};
   float frequency_{};
   float duty_{0.0f};
+  uint32_t last_duty_{UINT32_MAX};
   bool initialized_ = false;
 };
 
@@ -56,7 +57,6 @@ template<typename... Ts> class SetFrequencyAction : public Action<Ts...> {
   LEDCOutput *parent_;
 };
 
-}  // namespace ledc
-}  // namespace esphome
+}  // namespace esphome::ledc
 
 #endif

esphome/components/libretiny/helpers.cpp

@@ -26,9 +26,7 @@ void Mutex::unlock() { xSemaphoreGive(this->handle_); }
 IRAM_ATTR InterruptLock::InterruptLock() { portDISABLE_INTERRUPTS(); }
 IRAM_ATTR InterruptLock::~InterruptLock() { portENABLE_INTERRUPTS(); }
 
-// LibreTiny doesn't support lwIP core locking, so this is a no-op
-LwIPLock::LwIPLock() {}
-LwIPLock::~LwIPLock() {}
+// LibreTiny LwIPLock is defined inline as a no-op in helpers.h
 
 void get_mac_address_raw(uint8_t *mac) {  // NOLINT(readability-non-const-parameter)
   WiFi.macAddress(mac);

esphome/components/light/light_call.cpp

@@ -214,7 +214,14 @@ LightColorValues LightCall::validate_() {
   if (this->has_brightness() && this->brightness_ == 0.0f) {
     this->state_ = false;
     this->set_flag_(FLAG_HAS_STATE);
-    this->brightness_ = 1.0f;
+    if (color_mode & ColorCapability::BRIGHTNESS) {
+      // Reset brightness so the light has nonzero brightness when turned back on.
+      this->brightness_ = 1.0f;
+    } else {
+      // Light doesn't support brightness; clear the flag to avoid a spurious
+      // "brightness not supported" warning during capability validation.
+      this->clear_flag_(FLAG_HAS_BRIGHTNESS);
+    }
   }
 
   // Set color brightness to 100% if currently zero and a color is set.
@@ -506,7 +513,7 @@ color_mode_bitmask_t LightCall::get_suitable_color_modes_mask_() {
 
 LightCall &LightCall::set_effect(const char *effect, size_t len) {
   if (len == 4 && strncasecmp(effect, "none", 4) == 0) {
-    this->set_effect(0);
+    this->set_effect(uint32_t{0});
     return *this;
   }
 

esphome/components/light/light_call.h

@@ -130,6 +130,8 @@ class LightCall {
   LightCall &set_effect(optional<std::string> effect);
   /// Set the effect of the light by its name.
   LightCall &set_effect(const std::string &effect) { return this->set_effect(effect.data(), effect.size()); }
+  /// Set the effect of the light by its name (const char * overload to resolve ambiguity).
+  LightCall &set_effect(const char *effect) { return this->set_effect(effect, strlen(effect)); }
   /// Set the effect of the light by its name and length (zero-copy from API).
   LightCall &set_effect(const char *effect, size_t len);
   /// Set the effect of the light by its internal index number (only for internal use).

esphome/components/logger/logger_esp32.cpp

@@ -1,6 +1,7 @@
 #ifdef USE_ESP32
 #include "logger.h"
 
+#include "esphome/components/esp32/crash_handler.h"
 #include <esp_log.h>
 
 #include <driver/uart.h>
@@ -117,6 +118,9 @@ void Logger::pre_setup() {
   esp_log_set_vprintf(esp_idf_log_vprintf_);
 
   ESP_LOGI(TAG, "Log initialized");
+#ifdef USE_ESP32_CRASH_HANDLER
+  esp32::crash_handler_log();
+#endif
 }
 
 void HOT Logger::write_msg_(const char *msg, uint16_t len) {

esphome/components/logger/logger_rp2040.cpp

@@ -1,6 +1,9 @@
 #ifdef USE_RP2040
 #include "logger.h"
+#include "esphome/core/defines.h"
+#ifdef USE_RP2040_CRASH_HANDLER
 #include "esphome/components/rp2040/crash_handler.h"
+#endif
 #include "esphome/core/log.h"
 
 namespace esphome::logger {
@@ -26,7 +29,9 @@ void Logger::pre_setup() {
   }
   global_logger = this;
   ESP_LOGI(TAG, "Log initialized");
+#ifdef USE_RP2040_CRASH_HANDLER
   rp2040::crash_handler_log();
+#endif
 }
 
 void HOT Logger::write_msg_(const char *msg, uint16_t len) {

esphome/components/mdns/mdns_component.h

@@ -129,6 +129,10 @@ class MDNSComponent final : public Component {
 #endif
 #ifdef USE_MDNS_STORE_SERVICES
   StaticVector<MDNSService, MDNS_SERVICE_COUNT> services_{};
+#endif
+#ifdef USE_RP2040
+  bool was_connected_{false};
+  bool initialized_{false};
 #endif
   void compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services, char *mac_address_buf);
 };

esphome/components/mdns/mdns_rp2040.cpp

@@ -7,7 +7,12 @@
 #include "esphome/core/log.h"
 #include "mdns_component.h"
 
+// Arduino-Pico's PolledTimeout.h (pulled in by ESP8266mDNS.h) redefines IRAM_ATTR to empty.
+// Save and restore our definition around the include to avoid a redefinition warning.
+#pragma push_macro("IRAM_ATTR")
+#undef IRAM_ATTR
 #include <ESP8266mDNS.h>
+#pragma pop_macro("IRAM_ATTR")
 
 namespace esphome::mdns {
 
@@ -36,12 +41,32 @@ static void register_rp2040(MDNSComponent *, StaticVector<MDNSService, MDNS_SERV
 }
 
 void MDNSComponent::setup() {
-  this->setup_buffers_and_register_(register_rp2040);
-  // Schedule MDNS.update() via set_interval() instead of overriding loop().
-  // This removes the component from the per-iteration loop list entirely,
-  // eliminating virtual dispatch overhead on every main loop cycle.
-  // See MDNS_UPDATE_INTERVAL_MS comment in mdns_component.h for safety analysis.
-  this->set_interval(MDNS_UPDATE_INTERVAL_MS, []() { MDNS.update(); });
+  // RP2040's LEAmDNS library registers a LwipIntf::stateUpCB() callback to restart
+  // mDNS when the network interface reconnects. However, stateUpCB() is stubbed out
+  // in arduino-pico's LwipIntfCB.cpp because the original ESP8266 implementation used
+  // schedule_function() which doesn't exist in arduino-pico, and the callback can't
+  // safely run directly since netif status callbacks fire from IRQ context
+  // (PICO_CYW43_ARCH_THREADSAFE_BACKGROUND) while _restart() allocates UDP sockets.
+  //
+  // Workaround: defer MDNS.begin() and service registration until the network is
+  // connected (has an IP), then call notifyAPChange() on subsequent reconnects to
+  // restart mDNS probing and announcing — all from main loop context so it's
+  // thread-safe.
+  this->set_interval(MDNS_UPDATE_INTERVAL_MS, [this]() {
+    bool connected = network::is_connected();
+    if (connected && !this->was_connected_) {
+      if (!this->initialized_) {
+        this->setup_buffers_and_register_(register_rp2040);
+        this->initialized_ = true;
+      } else {
+        MDNS.notifyAPChange();
+      }
+    }
+    this->was_connected_ = connected;
+    if (this->initialized_) {
+      MDNS.update();
+    }
+  });
 }
 
 void MDNSComponent::on_shutdown() {

esphome/components/modbus/modbus.cpp

@@ -125,13 +125,17 @@ bool Modbus::parse_modbus_byte_(uint8_t byte) {
   // Byte 0: modbus address (match all)
   if (at == 0)
     return true;
-  uint8_t address = raw[0];
-  uint8_t function_code = raw[1];
+  // Byte 1: function code
+  if (at == 1)
+    return true;
   // Byte 2: Size (with modbus rtu function code 4/3)
   // See also https://en.wikipedia.org/wiki/Modbus
   if (at == 2)
     return true;
 
+  uint8_t address = raw[0];
+  uint8_t function_code = raw[1];
+
   uint8_t data_len = raw[2];
   uint8_t data_offset = 3;
 
@@ -146,10 +150,6 @@ bool Modbus::parse_modbus_byte_(uint8_t byte) {
     // chance that this is a complete message ... admittedly there is a small chance is
     // isn't but that is quite small given the purpose of the CRC in the first place
 
-    // Fewer than 2 bytes can't calc CRC
-    if (at < 2)
-      return true;
-
     data_len = at - 2;
     data_offset = 1;
 

esphome/components/online_image/online_image.cpp

@@ -129,7 +129,7 @@ void OnlineImage::update() {
   }
 
   ESP_LOGI(TAG, "Downloading image (Size: %zu)", total_size);
-  this->start_time_ = ::time(nullptr);
+  this->start_time_ = millis();
   this->enable_loop();
 }
 
@@ -155,8 +155,8 @@ void OnlineImage::loop() {
     // Finalize decoding
     this->end_decode();
 
-    ESP_LOGD(TAG, "Image fully downloaded, %zu bytes in %" PRIu32 "s", this->downloader_->get_bytes_read(),
-             (uint32_t) (::time(nullptr) - this->start_time_));
+    ESP_LOGD(TAG, "Image fully downloaded, %zu bytes in %" PRIu32 " ms", this->downloader_->get_bytes_read(),
+             millis() - this->start_time_);
 
     // Save caching headers
     this->etag_ = this->downloader_->get_response_header(ETAG_HEADER_NAME);

esphome/components/online_image/online_image.h

@@ -97,7 +97,7 @@ class OnlineImage : public PollingComponent,
    */
   std::string last_modified_ = "";
 
-  time_t start_time_;
+  uint32_t start_time_{0};
 };
 
 template<typename... Ts> class OnlineImageSetUrlAction : public Action<Ts...> {

esphome/components/ota/ota_backend_esp8266.cpp

@@ -105,6 +105,7 @@ OTAResponseTypes ESP8266OTABackend::begin(size_t image_size) {
 
   this->current_address_ = this->start_address_;
   this->image_size_ = image_size;
+  this->bytes_received_ = 0;
   this->buffer_len_ = 0;
   this->md5_set_ = false;
 
@@ -140,6 +141,7 @@ OTAResponseTypes ESP8266OTABackend::write(uint8_t *data, size_t len) {
     size_t to_buffer = std::min(len - written, this->buffer_size_ - this->buffer_len_);
     memcpy(this->buffer_.get() + this->buffer_len_, data + written, to_buffer);
     this->buffer_len_ += to_buffer;
+    this->bytes_received_ += to_buffer;
     written += to_buffer;
 
     // If buffer is full, write to flash
@@ -252,8 +254,8 @@ OTAResponseTypes ESP8266OTABackend::end() {
     }
   }
 
-  // Calculate actual bytes written
-  size_t actual_size = this->current_address_ - this->start_address_;
+  // Calculate actual bytes written (exact uploaded size, excluding flash write padding)
+  size_t actual_size = this->bytes_received_;
 
   // Check if any data was written
   if (actual_size == 0) {
@@ -304,6 +306,7 @@ void ESP8266OTABackend::abort() {
   this->buffer_.reset();
   this->buffer_len_ = 0;
   this->image_size_ = 0;
+  this->bytes_received_ = 0;
   esp8266::preferences_prevent_write(false);
 }
 

esphome/components/ota/ota_backend_esp8266.h

@@ -48,6 +48,7 @@ class ESP8266OTABackend final {
   uint32_t start_address_{0};
   uint32_t current_address_{0};
   size_t image_size_{0};
+  size_t bytes_received_{0};
 
   md5::MD5Digest md5_{};
   uint8_t expected_md5_[16];  // Fixed-size buffer for 128-bit (16-byte) MD5 digest

esphome/components/rp2040/__init__.py

@@ -203,7 +203,12 @@ async def to_code(config):
             cg.add_build_flag(f"-Wl,--wrap={symbol}")
 
     cg.add_platformio_option("board_build.core", "earlephilhower")
-    cg.add_platformio_option("board_build.filesystem_size", "1m")
+    # In testing mode, use all flash for sketch to allow linking grouped component tests.
+    # Real RP2040 hardware uses 1MB filesystem + 1MB sketch, but CI tests may combine
+    # many components that exceed the 1MB sketch partition.
+    cg.add_platformio_option(
+        "board_build.filesystem_size", "0m" if CORE.testing_mode else "1m"
+    )
 
     ver: cv.Version = CORE.data[KEY_CORE][KEY_FRAMEWORK_VERSION]
     cg.add_define(
@@ -212,6 +217,7 @@ async def to_code(config):
     )
 
     cg.add_define("USE_RP2040_WATCHDOG_TIMEOUT", config[CONF_WATCHDOG_TIMEOUT])
+    cg.add_define("USE_RP2040_CRASH_HANDLER")
 
 
 def add_pio_file(component: str, key: str, data: str):

esphome/components/rp2040/core.cpp

@@ -1,8 +1,10 @@
 #ifdef USE_RP2040
 
 #include "core.h"
-#include "crash_handler.h"
 #include "esphome/core/defines.h"
+#ifdef USE_RP2040_CRASH_HANDLER
+#include "crash_handler.h"
+#endif
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 
@@ -25,7 +27,9 @@ void arch_restart() {
 }
 
 void arch_init() {
+#ifdef USE_RP2040_CRASH_HANDLER
   rp2040::crash_handler_read_and_clear();
+#endif
 #if USE_RP2040_WATCHDOG_TIMEOUT > 0
   watchdog_enable(USE_RP2040_WATCHDOG_TIMEOUT, false);
 #endif

esphome/components/rp2040/crash_handler.cpp

@@ -1,5 +1,8 @@
 #ifdef USE_RP2040
 
+#include "esphome/core/defines.h"
+#ifdef USE_RP2040_CRASH_HANDLER
+
 #include "crash_handler.h"
 #include "esphome/core/log.h"
 
@@ -13,13 +16,19 @@
 static constexpr uint32_t EF_LR = 5;
 static constexpr uint32_t EF_PC = 6;
 
-static constexpr uint32_t CRASH_MAGIC = 0xDEADBEEF;
+// Version encoded in the magic value: upper 16 bits are sentinel (0xDEAD),
+// lower 16 bits are the version number. This avoids using a separate scratch
+// register for versioning (we only have 8 total). Future firmware reads the
+// sentinel to confirm it's crash data, then the version to know the layout.
+static constexpr uint32_t CRASH_MAGIC_SENTINEL = 0xDEAD0000;
+static constexpr uint32_t CRASH_DATA_VERSION = 1;
+static constexpr uint32_t CRASH_MAGIC_V1 = CRASH_MAGIC_SENTINEL | CRASH_DATA_VERSION;
 
 // We only have 8 scratch registers (32 bytes) that survive watchdog reboot.
 // Use them for the most important data, then scan the stack for code addresses.
 //
 // Scratch register layout:
-// [0] = magic (CRASH_MAGIC)
+// [0] = versioned magic (upper 16 bits = 0xDEAD sentinel, lower 16 bits = version)
 // [1] = PC (program counter at fault)
 // [2] = LR (link register from exception frame)
 // [3] = SP (stack pointer at fault)
@@ -48,18 +57,21 @@ static const char *const TAG = "rp2040.crash";
 
 // Placed in .noinit so BSS zero-init cannot race with crash_handler_read_and_clear().
 // The valid field is explicitly cleared in crash_handler_read_and_clear() instead.
-static struct {
+static struct CrashData {
   bool valid;
   uint32_t pc;
   uint32_t lr;
   uint32_t sp;
   uint32_t backtrace[MAX_BACKTRACE];
   uint8_t backtrace_count;
-} __attribute__((section(".noinit"))) s_crash_data;
+} s_crash_data __attribute__((section(".noinit")));
+
+bool crash_handler_has_data() { return s_crash_data.valid; }
 
 void crash_handler_read_and_clear() {
   s_crash_data.valid = false;
-  if (watchdog_hw->scratch[0] == CRASH_MAGIC) {
+  uint32_t magic = watchdog_hw->scratch[0];
+  if ((magic & 0xFFFF0000) == CRASH_MAGIC_SENTINEL && (magic & 0xFFFF) == CRASH_DATA_VERSION) {
     s_crash_data.valid = true;
     s_crash_data.pc = watchdog_hw->scratch[1];
     s_crash_data.lr = watchdog_hw->scratch[2];
@@ -135,7 +147,7 @@ static void __attribute__((used, noreturn)) hard_fault_handler_c(uint32_t *frame
   // by a stacking error or corrupted SP, frame may be invalid. Write a minimal
   // crash marker so we at least know a crash occurred.
   if (!is_valid_sram_ptr(frame)) {
-    watchdog_hw->scratch[0] = CRASH_MAGIC;
+    watchdog_hw->scratch[0] = CRASH_MAGIC_V1;
     watchdog_hw->scratch[1] = 0;                                   // PC unknown
     watchdog_hw->scratch[2] = 0;                                   // LR unknown
     watchdog_hw->scratch[3] = reinterpret_cast<uintptr_t>(frame);  // Record the bad SP for diagnosis
@@ -157,7 +169,7 @@ static void __attribute__((used, noreturn)) hard_fault_handler_c(uint32_t *frame
   uint32_t pre_fault_sp = reinterpret_cast<uintptr_t>(post_frame);
 
   // Write key registers
-  watchdog_hw->scratch[0] = CRASH_MAGIC;
+  watchdog_hw->scratch[0] = CRASH_MAGIC_V1;
   watchdog_hw->scratch[1] = frame[EF_PC];
   watchdog_hw->scratch[2] = frame[EF_LR];
   watchdog_hw->scratch[3] = pre_fault_sp;
@@ -224,4 +236,5 @@ extern "C" void __attribute__((naked, used)) isr_hardfault() {
                  : "i"(hard_fault_handler_c));
 }
 
+#endif  // USE_RP2040_CRASH_HANDLER
 #endif  // USE_RP2040

esphome/components/rp2040/crash_handler.h

@@ -2,7 +2,9 @@
 
 #ifdef USE_RP2040
 
-#include <cstdint>
+#include "esphome/core/defines.h"
+
+#ifdef USE_RP2040_CRASH_HANDLER
 
 namespace esphome::rp2040 {
 
@@ -12,6 +14,10 @@ void crash_handler_read_and_clear();
 /// Log crash data if a crash was detected on previous boot.
 void crash_handler_log();
 
+/// Returns true if crash data was found this boot.
+bool crash_handler_has_data();
+
 }  // namespace esphome::rp2040
 
+#endif  // USE_RP2040_CRASH_HANDLER
 #endif  // USE_RP2040

esphome/components/runtime_image/bmp_decoder.h

@@ -26,6 +26,10 @@ class BmpDecoder : public ImageDecoder {
   int HOT decode(uint8_t *buffer, size_t size) override;
 
   bool is_finished() const override {
+    if (this->bits_per_pixel_ == 0) {
+      // header not yet received, so dimensions not yet determined
+      return false;
+    }
     // BMP is finished when we've decoded all pixel data
     return this->paint_index_ >= static_cast<size_t>(this->width_ * this->height_);
   }