diff --git a/libraries/AP_HAL_ChibiOS/hwdef/AeroCogito-H7Digital/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/AeroCogito-H7Digital/hwdef.dat
index c71acd538c2..03f4b2cf4d6 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/AeroCogito-H7Digital/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/AeroCogito-H7Digital/hwdef.dat
@@ -155,7 +155,6 @@ define OSD_ENABLED 1
 define HAL_OSD_TYPE_DEFAULT 5   # MSP DisplayPort
 
 # Sensor configuration
-define ALLOW_ARM_NO_GPS         # Allow arming without GPS
 define AP_COMPASS_PROBING_ENABLED 1
 
 # ESC telemetry support
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/CubeRedSecondary-IO/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/CubeRedSecondary-IO/hwdef.dat
index 5e0327128e0..dc10007d29b 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/CubeRedSecondary-IO/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/CubeRedSecondary-IO/hwdef.dat
@@ -125,10 +125,7 @@ define HAL_USE_UART TRUE
 define STM32_UART_USE_UART7 TRUE
 define HAL_IO_FMU_COMMS UARTD7
 define HAL_IO_FMU_COMMS_TX_DMA_STREAM STM32_UART_UART7_TX_DMA_STREAM
-define HAL_IO_FMU_COMMS_TX_DMA_CHANNEL STM32_UART_UART7_TX_DMA_CHAN
 define HAL_IO_FMU_COMMS_TX_IRQ_PRIORITY STM32_UART_UART7_IRQ_PRIORITY
-define HAL_IO_FMU_COMMS_RX_DMA_STREAM STM32_UART_UART7_RX_DMA_STREAM
-define HAL_IO_FMU_COMMS_RX_DMA_CHANNEL STM32_UART_UART7_RX_DMA_CHAN
 
 define HAL_USE_SERIAL TRUE
 define STM32_SERIAL_USE_UART7 FALSE
@@ -154,7 +151,6 @@ define HAL_IOMCU_APP_LOAD_ADDRESS 0x08020000
 
 define IOMCU_DEBUG SD8
 define STM32_SERIAL_USE_UART8 TRUE
-define HAL_BL_IOMCU_FW_DETECT 1
 
 define AP_HAL_UARTDRIVER_ENABLED 0
 define HAL_SERIAL_SBUS_SWAPPED 1
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/GreenSightUltraBlue/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/GreenSightUltraBlue/hwdef.dat
index 224b981f225..4937981148a 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/GreenSightUltraBlue/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/GreenSightUltraBlue/hwdef.dat
@@ -289,7 +289,6 @@ define HAL_DEFAULT_INS_FAST_SAMPLE 5
 # format is COMPASS <driver> <I2C/SPI>:<bus>:<address> <force_external> <rotation>
 
 COMPASS IST8308 I2C:1:0x0E false ROTATION_ROLL_180_YAW_90
-define AP_COMPASS_IST8308_DEFAULT_ROTATION ROTATION_ROLL_180_YAW_90
 
 COMPASS IST8310 I2C:1:0x0E false ROTATION_ROLL_180
 define AP_COMPASS_IST8310_DEFAULT_ROTATION ROTATION_ROLL_180
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat
index eced560679a..2eca6fd4273 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/KakuteF4/hwdef.dat
@@ -114,7 +114,6 @@ PA3 TIM5_CH4 TIM5 PWM(3) GPIO(52)
 PA2 TIM5_CH3 TIM5 PWM(4) GPIO(53)
 
 PC8 TIM8_CH3 TIM8 PWM(5) GPIO(54) # LED strip
-define HAL_NEOPIXEL_COUNT 8
 
 define HAL_STORAGE_SIZE 15360
 STORAGE_FLASH_PAGE 2
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/NucleoH753ZI/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/NucleoH753ZI/hwdef.dat
index c036199e1f2..3ce2dce3332 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/NucleoH753ZI/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/NucleoH753ZI/hwdef.dat
@@ -138,13 +138,6 @@ define HAL_USB_ENABLE_COMMENTS "SB76 must be ON for USB OTG_FS to work"
 PB8  I2C1_SCL I2C1
 PB9  I2C1_SDA I2C1
 
-define HAL_BLHELI_PASSTHROUGH_ENABLED 1
-define HAL_BLHELI_PASSTHROUGH_UART 3
-# UART ESC support (for ESC telemetry via UART)
-# UART1 can be used for ESC telemetry
-define HAL_ESC_TELEMETRY_UART_ENABLED 1
-define HAL_ESC_TELEMETRY_UART 1
-
 # UARTs 
 PB6  USART1_TX USART1
 PB7  USART1_RX USART1
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/OrqaH7QuadCore/hwdef-bl.dat b/libraries/AP_HAL_ChibiOS/hwdef/OrqaH7QuadCore/hwdef-bl.dat
index 2fd6fd93cfc..b700beb954a 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/OrqaH7QuadCore/hwdef-bl.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/OrqaH7QuadCore/hwdef-bl.dat
@@ -39,7 +39,6 @@ PD0 CAM_SW OUTPUT LOW
 
 PA8 LED_BOOTLOADER OUTPUT LOW
 define HAL_LED_ON 1
-define HAL_LED_OFF 0
 
 # FATFS support:
 define CH_CFG_USE_MEMCORE 1
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/PilotGaeaSH7V1-bdshot/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/PilotGaeaSH7V1-bdshot/hwdef.dat
index 4f898f38ed6..9828fadc74f 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/PilotGaeaSH7V1-bdshot/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/PilotGaeaSH7V1-bdshot/hwdef.dat
@@ -3,7 +3,6 @@
 
 # MCU class and specific type
 MCU STM32H7xx STM32H743xx
-define HAL_BOOTLOADER_NAME "PilotGaeaSH7V1-bdshot_bl.bin"
 
 # board ID for firmware load
 APJ_BOARD_ID AP_HW_PilotGaeaSH7V1
@@ -164,7 +163,6 @@ define HAL_STORAGE_SIZE 32768
 # use last 2 pages for flash storage
 # H743 has 16 pages of 128k each
 STORAGE_FLASH_PAGE 14
-define HAL_BOOTLOADER_BOOT_FROM_SDCARD 1
 
 # spi devices
 SPIDEV icm42688_0 SPI1 DEVID1 IMU1_CS  MODE3  2*MHZ 16*MHZ
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/SIMPLIFLYH7/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/SIMPLIFLYH7/hwdef.dat
index bcbae51bc8c..2e53ba9e9b8 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/SIMPLIFLYH7/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/SIMPLIFLYH7/hwdef.dat
@@ -134,7 +134,6 @@ define AP_NOTIFY_GPIO_LED_1_PIN 90
 # actively driven LOW = buzzer sounds.
 PD3 BUZZER OUTPUT HIGH GPIO(80) OPENDRAIN PULLUP
 define HAL_BUZZER_PIN 80
-define HAL_BUZZER_ON 0
 
 # -------------------------------------------------
 # MOTORS - TIM8 (PC6-PC9)
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/SkyRukh_Surge_H7/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/SkyRukh_Surge_H7/hwdef.dat
index 13dfac72d62..db1d4134354 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/SkyRukh_Surge_H7/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/SkyRukh_Surge_H7/hwdef.dat
@@ -184,10 +184,6 @@ define AP_NOTIFY_GPIO_LED_RGB_RED_PIN 10
 define AP_NOTIFY_GPIO_LED_RGB_GREEN_PIN 11
 define AP_NOTIFY_GPIO_LED_RGB_BLUE_PIN 12
 
-# CAN 
-define HAL_CAN_ENABLED      1
-define HAL_CAN_NUM_DRIVERS 1
-
 # enable RAMTROM parameter storage
 define HAL_STORAGE_SIZE 32768
 define HAL_WITH_RAMTRON 1
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/SkystarsH7HD/hwdef-bl.dat b/libraries/AP_HAL_ChibiOS/hwdef/SkystarsH7HD/hwdef-bl.dat
index 01b5f9df7f5..cb1285560fe 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/SkystarsH7HD/hwdef-bl.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/SkystarsH7HD/hwdef-bl.dat
@@ -36,7 +36,6 @@ PB3 BUZZER OUTPUT LOW
 PE3 LED_BOOTLOADER OUTPUT HIGH
 PE4 LED_ACTIVITY OUTPUT HIGH
 define HAL_LED_ON 0
-define HAL_LED_OFF 1
 
 
 
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/VM-L431-BMS/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/VM-L431-BMS/hwdef.dat
index 5f382e0604b..cd5694cdcbc 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/VM-L431-BMS/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/VM-L431-BMS/hwdef.dat
@@ -20,7 +20,6 @@ STDOUT_SERIAL SD2
 # enable battery monitor
 define AP_PERIPH_BATTERY_ENABLED 1
 define AP_BATTERY_TIBQ76952_ENABLED 1
-define AP_BATTERY_TIBQ76952_I2C_DEVICE "tibq76952"
 define HAL_BATT_MONITOR_DEFAULT 32
 define AP_PERIPH_BATTERY_MODEL_NAME "VM-L431-BMS"
 
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/ZeroOneX6/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/ZeroOneX6/hwdef.dat
index 8d422037bb3..8865e1a3f08 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/ZeroOneX6/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/ZeroOneX6/hwdef.dat
@@ -295,10 +295,6 @@ COMPASS RM3100 I2C:0:0x20 false ROTATION_NONE
 COMPASS IST8310 I2C:0:0x0E false ROTATION_PITCH_180
 COMPASS BMM350 I2C:0:0x15 false ROTATION_ROLL_180_YAW_270
 
-# compensate for magnetic field generated by the heater on ZeroOne X6 RM3100
-define HAL_HEATER_MAG_OFFSET_RM3100 AP_HAL::Device::make_bus_id(AP_HAL::Device::BUS_TYPE_I2C,0,0x20,0x11),Vector3f(0,0,0)
-
-#define HAL_HEATER_MAG_OFFSET HAL_HEATER_MAG_OFFSET_RM3100
  
 # IMU devices for ZeroOne X6
 SPIDEV icm45686_1  SPI2 DEVID1  SP2_CS1 MODE3  2*MHZ  16*MHZ
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/rFCU/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/rFCU/hwdef.dat
index 9f6415ce0ca..8e08ef58fab 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/rFCU/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/rFCU/hwdef.dat
@@ -212,8 +212,6 @@ PB5  HEATER4_EN OUTPUT LOW GPIO(83) # control board, GPIO2
 
 define HAL_HEATER_GPIO_PIN 80
 define HAL_HEATER2_GPIO_PIN 81
-define HAL_HEATER3_GPIO_PIN 82
-define HAL_HEATER4_GPIO_PIN 83
 
 # the heater impacts the RM3100 compass
 define HAL_HEATER_MAG_OFFSET {AP_HAL::Device::make_bus_id(AP_HAL::Device::BUS_TYPE_SPI,1,0x2,0x11),Vector3f(60,7,-11)}
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/sparknavi-blue/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/sparknavi-blue/hwdef.dat
index 14581b72c51..161c7283d39 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/sparknavi-blue/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/sparknavi-blue/hwdef.dat
@@ -207,11 +207,6 @@ PE15 VDD_BRICK_VALID INPUT PULLDOWN
 
 #This maps to the MAV_POWER_STATUS_SERVO_VALID in mavlink
 #see AnalogIn.cpp
-#secondary "brick" power supply valid pin. This is servo rail power valid on some boards. Some boards have this active high,
-#some active low. Use nVALID for active low, VALID for active high. This maps to the MAV_POWER_STATUS_SERVO_VALID in mavlink
-#(as this was first added for older boards that used servo rail for backup power)
-
-define VDD_BRICK2_VALID 1
 
 define HAL_BATT_MONITOR_DEFAULT 4  # Analog voltage and current
 define HAL_BATT2_MONITOR_DEFAULT 4  # Analog voltage and current