diff --git a/README.md b/README.md
index 6a7faf9..b943d0c 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 Latest build date is 20241208, see the [changelog](changelog.md) for details.  
 
 > [!NOTE]
->  A settings reset will be performed on an update of builds prior to 20241208. Backup and restore of settings is recommended.  
+>  A settings reset will be performed on an update of builds prior to 20241217. Backup and restore of settings is recommended.  
 
 > [!NOTE]
 >  Build 20240222 has moved the probe input to the ioPorts pool of inputs and will be allocated from it when configured.
@@ -93,4 +93,4 @@ G/M-codes not supported by [legacy Grbl](https://github.com/gnea/grbl/wiki) are
 Some [plugins](https://github.com/grblHAL/plugins) implements additional M-codes.
 
 ---
-20241209
+20241217
diff --git a/changelog.md b/changelog.md
index 26f6f2d..3c43501 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,23 @@
 ## grblHAL changelog
 
+<a name="20241217">Build 20241217
+
+Core:
+
+* Added preprocessor support for moving coolant outputs to auxiliary pool. Some minor bug fixes and code cleanup.  
+Those who have custom board maps must update pin assignments accordingly when updating to this or later versions.
+
+Drivers:
+
+* Most: moved coolant outputs to auxiliary outputs pool for many boards.  
+Web Builder functionality for assigning those outputs as coolant or as auxiliary (controlled by M62-M65) will be forthcoming.
+
+* ESP32: added driver support for second PWM spindle, only configurable for the MKS DLC32 v2 board for now.
+
+Plugins:
+
+* Spindle: removed obsoleted code, fix for second PWM spindle w/o direction output.
+
 <a name="20241214">Build 20241214
 
 Core:
diff --git a/coolant_control.h b/coolant_control.h
index be93609..81f4aba 100644
--- a/coolant_control.h
+++ b/coolant_control.h
@@ -25,8 +25,9 @@
 
 // if changed to > 8 bits planner_cond_t needs to be changed too
 typedef union {
+    uint8_t bits;                  //!< Bitmask bits
+    uint8_t mask;                  //!< Bitmask
     uint8_t value;                 //!< Bitmask value
-    uint8_t mask;                  //!< Synonym for bitmask value
     struct {
         uint8_t flood          :1, //!< Flood coolant.
                 mist           :1, //!< Mist coolant, optional.
diff --git a/crossbar.h b/crossbar.h
index 0c13722..7fd5f88 100644
--- a/crossbar.h
+++ b/crossbar.h
@@ -165,7 +165,11 @@ typedef enum {
     Output_Aux9,
     Output_Aux10,
     Output_Aux11,
-    Output_AuxMax = Output_Aux11,
+    Output_Aux12,
+    Output_Aux13,
+    Output_Aux14,
+    Output_Aux15,
+    Output_AuxMax = Output_Aux15,
     Output_Analog_Aux0,
     Output_Analog_Aux1,
     Output_Analog_Aux2,
@@ -376,6 +380,10 @@ PROGMEM static const pin_name_t pin_names[] = {
     { .function = Output_Aux9,                .name = "Aux out 9" },
     { .function = Output_Aux10,               .name = "Aux out 10" },
     { .function = Output_Aux11,               .name = "Aux out 11" },
+    { .function = Output_Aux12,               .name = "Aux out 12" },
+    { .function = Output_Aux13,               .name = "Aux out 13" },
+    { .function = Output_Aux14,               .name = "Aux out 14" },
+    { .function = Output_Aux15,               .name = "Aux out 15" },
     { .function = Output_Analog_Aux0,         .name = "Aux analog out 0" },
     { .function = Output_Analog_Aux1,         .name = "Aux analog out 1" },
     { .function = Output_Analog_Aux2,         .name = "Aux analog out 2" },
diff --git a/driver_opts.h b/driver_opts.h
index fce192b..a724b23 100644
--- a/driver_opts.h
+++ b/driver_opts.h
@@ -231,6 +231,51 @@
 #endif
 #endif
 
+#ifndef ESTOP_ENABLE
+  #if COMPATIBILITY_LEVEL <= 1
+    #define ESTOP_ENABLE    1
+  #else
+    #define ESTOP_ENABLE    0
+  #endif
+#elif ESTOP_ENABLE && COMPATIBILITY_LEVEL > 1
+  #warning "Enabling ESTOP may not work with all senders!"
+#endif
+
+#define AUX_CONTROL_SPINDLE 0b0001
+#define AUX_CONTROL_COOLANT 0b0010
+#define AUX_CONTROL_DEVICES 0b0100
+#define AUX_CONTROL_INPUTS  0b1000
+
+// Control signals, keep in sync with control_signals_t
+#define CONTROL_RESET       0b0000001
+#define CONTROL_FEEDHOLD    0b0000010
+#define CONTROL_CYCLESTART  0b0000100
+#define CONTROL_SAFETYDOOR  0b0001000
+#define CONTROL_BLOCKDELETE 0b0010000
+#define CONTROL_STOPDISABLE 0b0100000
+#define CONTROL_ESTOP       0b1000000
+
+#ifndef CONTROL_ENABLE
+#if ESTOP_ENABLE
+#define CONTROL_ENABLE      (CONTROL_FEEDHOLD|CONTROL_CYCLESTART|CONTROL_ESTOP)
+#else
+#define CONTROL_ENABLE      (CONTROL_RESET|CONTROL_FEEDHOLD|CONTROL_CYCLESTART)
+#endif
+#endif
+
+// Coolant signals, keep in sync with coolant_state_t
+#define COOLANT_FLOOD       0b01
+#define COOLANT_MIST        0b10
+
+#ifndef COOLANT_ENABLE
+#define COOLANT_ENABLE      (COOLANT_FLOOD|COOLANT_MIST)
+#endif
+
+// Spindle signals
+#define SPINDLE_ENA         0b001
+#define SPINDLE_PWM         0b010
+#define SPINDLE_DIR         0b100
+
 #ifndef SPINDLE0_ENABLE
 #define SPINDLE0_ENABLE DEFAULT_SPINDLE
 #endif
@@ -269,23 +314,29 @@
 
 // Driver spindle 0
 
-#if SPINDLE_ENABLE & ((1<<SPINDLE_PWM0)|(1<<SPINDLE_PWM0_NODIR)|(1<<SPINDLE_ONOFF0)|(1<<SPINDLE_ONOFF0_DIR))
-#define DRIVER_SPINDLE_ENABLE       1
+#if SPINDLE_ENABLE & (1<<SPINDLE_PWM0)
+#define DRIVER_SPINDLE_ENABLE (SPINDLE_ENA|SPINDLE_PWM|SPINDLE_DIR)
+#elif SPINDLE_ENABLE & (1<<SPINDLE_PWM0_NODIR)
+#define DRIVER_SPINDLE_ENABLE (SPINDLE_ENA|SPINDLE_PWM)
+#elif SPINDLE_ENABLE & (1<<SPINDLE_ONOFF0)
+#define DRIVER_SPINDLE_ENABLE SPINDLE_ENA
+#elif SPINDLE_ENABLE & (1<<SPINDLE_ONOFF0_DIR)
+#define DRIVER_SPINDLE_ENABLE (SPINDLE_ENA|SPINDLE_DIR)
 #else
 #define DRIVER_SPINDLE_ENABLE       0
 #endif
 
-#if SPINDLE_ENABLE & ((1<<SPINDLE_PWM0)|(1<<SPINDLE_ONOFF0_DIR))
-#define DRIVER_SPINDLE_DIR_ENABLE   1
+#if DRIVER_SPINDLE_ENABLE & SPINDLE_DIR
+#define DRIVER_SPINDLE_DIR_ENABLE   1 // Deprecated
 #else
-#define DRIVER_SPINDLE_DIR_ENABLE   0
+#define DRIVER_SPINDLE_DIR_ENABLE   0 // Deprecated
 #endif
 
-#if SPINDLE_ENABLE & ((1<<SPINDLE_PWM0)|(1<<SPINDLE_PWM0_NODIR))
-#define DRIVER_SPINDLE_PWM_ENABLE  1
+#if DRIVER_SPINDLE_ENABLE & SPINDLE_PWM
+#define DRIVER_SPINDLE_PWM_ENABLE  1 // Deprecated
 #define DRIVER_SPINDLE_NAME "PWM"
 #else
-#define DRIVER_SPINDLE_PWM_ENABLE  0
+#define DRIVER_SPINDLE_PWM_ENABLE  0 // Deprecated
 #if DRIVER_SPINDLE_ENABLE
 #define DRIVER_SPINDLE_NAME "Basic"
 #endif
@@ -295,7 +346,15 @@
 
 #if SPINDLE_ENABLE & ((1<<SPINDLE_PWM1)|(1<<SPINDLE_PWM1_NODIR)|(1<<SPINDLE_ONOFF1)|(1<<SPINDLE_ONOFF1_DIR))
 #if N_SPINDLE > 1
-#define DRIVER_SPINDLE1_ENABLE       1
+#if SPINDLE_ENABLE & (1<<SPINDLE_PWM1)
+#define DRIVER_SPINDLE1_ENABLE (SPINDLE_ENA|SPINDLE_PWM|SPINDLE_DIR)
+#elif SPINDLE_ENABLE & (1<<SPINDLE_PWM1_NODIR)
+#define DRIVER_SPINDLE1_ENABLE (SPINDLE_ENA|SPINDLE_PWM)
+#elif SPINDLE_ENABLE & (1<<SPINDLE_ONOFF1)
+#define DRIVER_SPINDLE1_ENABLE SPINDLE_ENA
+#elif SPINDLE_ENABLE & (1<<SPINDLE_ONOFF1_DIR)
+#define DRIVER_SPINDLE1_ENABLE (SPINDLE_ENA|SPINDLE_DIR)
+#endif
 #else
 #warning "Configure N_SPINDLE > 1 in grbl/config.h when enabling second driver spindle!"
 #endif
@@ -303,17 +362,17 @@
 #define DRIVER_SPINDLE1_ENABLE       0
 #endif
 
-#if DRIVER_SPINDLE1_ENABLE && (SPINDLE_ENABLE & ((1<<SPINDLE_PWM1)|(1<<SPINDLE_ONOFF1_DIR)))
-#define DRIVER_SPINDLE1_DIR_ENABLE   1
+#if DRIVER_SPINDLE1_ENABLE & SPINDLE_DIR
+#define DRIVER_SPINDLE1_DIR_ENABLE   1 // Deprecated
 #else
-#define DRIVER_SPINDLE1_DIR_ENABLE   0
+#define DRIVER_SPINDLE1_DIR_ENABLE   0 // Deprecated
 #endif
 
-#if DRIVER_SPINDLE1_ENABLE && (SPINDLE_ENABLE & ((1<<SPINDLE_PWM1)|(1<<SPINDLE_PWM1_NODIR)))
-#define DRIVER_SPINDLE1_PWM_ENABLE  1
+#if DRIVER_SPINDLE1_ENABLE & SPINDLE_PWM
+#define DRIVER_SPINDLE1_PWM_ENABLE  1 // Deprecated
 #define DRIVER_SPINDLE1_NAME "PWM2"
 #else
-#define DRIVER_SPINDLE1_PWM_ENABLE  0
+#define DRIVER_SPINDLE1_PWM_ENABLE  0 // Deprecated
 #if DRIVER_SPINDLE1_ENABLE
 #define DRIVER_SPINDLE1_NAME "Basic2"
 #endif
@@ -416,16 +475,6 @@
 #error "Driver does not support safety door functionality!"
 #endif
 
-#ifndef ESTOP_ENABLE
-  #if COMPATIBILITY_LEVEL <= 1
-    #define ESTOP_ENABLE    1
-  #else
-    #define ESTOP_ENABLE    0
-  #endif
-#elif ESTOP_ENABLE && COMPATIBILITY_LEVEL > 1
-  #warning "Enabling ESTOP may not work with all senders!"
-#endif
-
 //
 
 #ifndef WIFI_ENABLE
diff --git a/driver_opts2.h b/driver_opts2.h
index 1e0238e..55254d2 100644
--- a/driver_opts2.h
+++ b/driver_opts2.h
@@ -25,28 +25,20 @@
 // NOTE: do NOT change options here - edit the driver specific my_machine.h instead!
 //
 
-#if DRIVER_SPINDLE_ENABLE && !defined(SPINDLE_ENABLE_PIN)
+#if (DRIVER_SPINDLE_ENABLE & SPINDLE_ENA) && !defined(SPINDLE_ENABLE_PIN)
 #warning "Selected spindle is not supported!"
-#undef DRIVER_SPINDLE_ENABLE
-#define DRIVER_SPINDLE_ENABLE 0
 #endif
 
-#if DRIVER_SPINDLE_DIR_ENABLE && !defined(SPINDLE_DIRECTION_PIN)
+#if (DRIVER_SPINDLE_ENABLE & SPINDLE_DIR) && !defined(SPINDLE_DIRECTION_PIN)
 #warning "Selected spindle is not fully supported - no direction output!"
-#undef DRIVER_SPINDLE_DIR_ENABLE
-#define DRIVER_SPINDLE_DIR_ENABLE 0
 #endif
 
-#if DRIVER_SPINDLE_PWM_ENABLE && (!DRIVER_SPINDLE_ENABLE || !defined(SPINDLE_PWM_PIN))
+#if (DRIVER_SPINDLE_ENABLE & SPINDLE_PWM) && !defined(SPINDLE_PWM_PIN)
 #warning "Selected spindle is not supported!"
-#undef DRIVER_SPINDLE_PWM_ENABLE
-#define DRIVER_SPINDLE_PWM_ENABLE 0
 #endif
 
-#if DRIVER_SPINDLE_PWM1_ENABLE && (!DRIVER_SPINDLE1_ENABLE || !defined(SPINDLE1_PWM_PIN))
+#if (DRIVER_SPINDLE1_ENABLE & SPINDLE_PWM) && !defined(SPINDLE_PWM_PIN)
 #warning "Selected spindle 1 is not supported!"
-#undef DRIVER_SPINDLE_PWM1_ENABLE
-#define DRIVER_SPINDLE_PWM1_ENABLE 0
 #endif
 
 #if MPG_ENABLE == 1 && !defined(MPG_MODE_PIN)
@@ -146,6 +138,12 @@
 #endif
 #endif
 
+#if defined(COPROC_RESET_PIN) && defined(COPROC_BOOT0_PIN)
+#define COPROC_PASSTHRU 1
+#else
+#define COPROC_PASSTHRU 0
+#endif
+
 #ifndef COPROC_STREAM
 #if USB_SERIAL_CDC
 #define COPROC_STREAM     0
diff --git a/grbl.h b/grbl.h
index 100168c..dfb2cf2 100644
--- a/grbl.h
+++ b/grbl.h
@@ -42,7 +42,7 @@
 #else
 #define GRBL_VERSION "1.1f"
 #endif
-#define GRBL_BUILD 20241214
+#define GRBL_BUILD 20241217
 
 #define GRBL_URL "https://github.com/grblHAL"
 
diff --git a/machine_limits.c b/machine_limits.c
index f781bd7..82b31a3 100644
--- a/machine_limits.c
+++ b/machine_limits.c
@@ -558,7 +558,7 @@ status_code_t limits_go_home (axes_signals_t cycle)
         // If axes in cycle has different feed rates home them separately
         if(axis0 == 254) {
 
-            status_code_t status;
+            status_code_t status = Status_OK;
 
             idx = 0;
             while(cycle.mask) {
diff --git a/pin_bits_masks.h b/pin_bits_masks.h
index a3d198d..5c16c43 100644
--- a/pin_bits_masks.h
+++ b/pin_bits_masks.h
@@ -392,42 +392,83 @@ static inline control_signals_t aux_ctrl_scan_status (control_signals_t signals)
 #define AUX_CONTROLS_SCAN    0
 #endif
 
-#ifdef AUX_CONTROLS_OUT
+#if defined(AUX_CONTROLS_OUT) && !defined(AUX_CONTROLS)
+#define AUX_CONTROLS AUX_CONTROL_SPINDLE
+#elif !defined(AUX_CONTROLS)
+#define AUX_CONTROLS 0
+#endif
+
+#if AUX_CONTROLS
 
 // The following pins are bound explicitly to aux output pins
 static aux_ctrl_out_t aux_ctrl_out[] = {
-#if DRIVER_SPINDLE_ENABLE
+#if AUX_CONTROLS & AUX_CONTROL_SPINDLE
+#ifdef SPINDLE_ENABLE_PIN
+ #ifndef SPINDLE_ENABLE_PORT
+  #define SPINDLE_ENABLE_PORT NULL
+ #endif
     { .function = Output_SpindleOn,    .aux_port = 0xFF, .pin = SPINDLE_ENABLE_PIN,     .port = SPINDLE_ENABLE_PORT },
-#if DRIVER_SPINDLE_PWM_ENABLE
+#endif
+#ifdef SPINDLE_PWM_PIN
+ #ifndef SPINDLE_PWM_PORT
+  #define SPINDLE_PWM_PORT NULL
+ #endif
     { .function = Output_SpindlePWM,   .aux_port = 0xFF, .pin = SPINDLE_PWM_PIN,        .port = SPINDLE_PWM_PORT },
 #endif
-#if DRIVER_SPINDLE_DIR_ENABLE
+#ifdef SPINDLE_DIRECTION_PIN
+ #ifndef SPINDLE_DIRECTION_PORT
+  #define SPINDLE_DIRECTION_PORT NULL
+ #endif
     { .function = Output_SpindleDir,   .aux_port = 0xFF, .pin = SPINDLE_DIRECTION_PIN,  .port = SPINDLE_DIRECTION_PORT },
 #endif
-#endif // DRIVER_SPINDLE_ENABLE
-#if DRIVER_SPINDLE1_ENABLE
+
+#ifdef SPINDLE1_ENABLE_PIN
+ #ifndef SPINDLE1_ENABLE_PORT
+  #define SPINDLE1_ENABLE_PORT NULL
+ #endif
     { .function = Output_Spindle1On,   .aux_port = 0xFF, .pin = SPINDLE1_ENABLE_PIN,    .port = SPINDLE1_ENABLE_PORT },
-#if DRIVER_SPINDLE1_PWM_ENABLE
+#endif
+#ifdef SPINDLE1_PWM_PIN
+ #ifndef SPINDLE1_PWM_PORT
+  #define SPINDLE1_PWM_PORT NULL
+ #endif
     { .function = Output_Spindle1PWM,  .aux_port = 0xFF, .pin = SPINDLE1_PWM_PIN,       .port = SPINDLE1_PWM_PORT },
 #endif
-#if DRIVER_SPINDLE1_DIR_ENABLE
+#ifdef SPINDLE1_DIRECTION_PIN
+ #ifndef SPINDLE1_DIRECTION_PORT
+  #define SPINDLE1_DIRECTION_PORT NULL
+ #endif
     { .function = Output_Spindle1Dir,  .aux_port = 0xFF, .pin = SPINDLE1_DIRECTION_PIN, .port = SPINDLE1_DIRECTION_PORT },
 #endif
-#endif // DRIVER_SPINDLE1_DIR_ENABLE
+#endif // SPINDLES
+
+#if AUX_CONTROLS & AUX_CONTROL_COOLANT
+#ifdef COOLANT_FLOOD_PIN
+ #ifndef COOLANT_FLOOD_PORT
+  #define COOLANT_FLOOD_PORT NULL
+ #endif
+    { .function = Output_CoolantFlood, .aux_port = 0xFF, .pin = COOLANT_FLOOD_PIN,      .port = COOLANT_FLOOD_PORT },
+#endif
+#ifdef COOLANT_MIST_PIN
+ #ifndef COOLANT_MIST_PORT
+  #define COOLANT_MIST_PORT NULL
+ #endif
+    { .function = Output_CoolantMist,  .aux_port = 0xFF, .pin = COOLANT_MIST_PIN,       .port = COOLANT_MIST_PORT },
+#endif
+#endif // COOLANT
+
 #ifdef COPROC_RESET_PIN
+ #ifndef COPROC_RESET_PORT
+  #define COPROC_RESET_PORT NULL
+ #endif
     { .function = Output_CoProc_Reset, .aux_port = 0xFF, .pin = COPROC_RESET_PIN,       .port = COPROC_RESET_PORT },
 #endif
 #ifdef COPROC_BOOT0_PIN
+ #ifndef COPROC_BOOT0_PORT
+  #define COPROC_BOOT0_PORT NULL
+ #endif
     { .function = Output_CoProc_Boot0, .aux_port = 0xFF, .pin = COPROC_BOOT0_PIN,       .port = COPROC_BOOT0_PORT },
 #endif
-/*
-#ifdef COOLANT_FLOOD_PIN
-    { .function = Output_CoolantFlood, .aux_port = 0xFF, .pin = COOLANT_FLOOD_PIN, .port = COOLANT_FLOOD_PORT },
-#endif
-#ifdef COOLANT_MIST_PIN
-    { .function = Output_CoolantMist, .aux_port = 0xFF, .pin = COOLANT_MIST_PIN, .port = COOLANT_MIST_PORT },
-#endif
-*/
 };
 
 static inline aux_ctrl_out_t *aux_out_remap_explicit (void *port, uint8_t pin, uint8_t aux_port, void *output)
@@ -473,7 +514,7 @@ static inline void aux_ctrl_claim_out_ports (aux_claim_explicit_out_ptr aux_clai
     }
 }
 
-#endif // AUX_CONTROLS_OUT
+#endif // AUX_CONTROLS
 
 //
 
diff --git a/plugins_init.h b/plugins_init.h
index 4cd6129..ed0fb39 100644
--- a/plugins_init.h
+++ b/plugins_init.h
@@ -58,7 +58,7 @@
     onoff_spindle_init();
 #endif
 
-#if SPINDLE_ENABLE & (1<<SPINDLE_PWM2)
+#if SPINDLE_ENABLE & ((1<<SPINDLE_PWM2)|(1<<SPINDLE_PWM2_NODIR))
     extern void pwm_spindle_init (void);
     pwm_spindle_init();
 #endif
diff --git a/settings.c b/settings.c
index c5af887..52c8422 100644
--- a/settings.c
+++ b/settings.c
@@ -2912,14 +2912,18 @@ status_code_t setting_validate (setting_id_t id, float value, char *svalue)
 
 static bool settings_changed_spindle (void)
 {
-    static spindle_settings_t spindle_settings = {0};
+    static spindle_settings_t spindle_settings = {};
+    static spindle_pwm_settings_t spindle_pwm_settings = {};
 
-    bool changed;
+    bool base_changed, pwm_changed;
 
-    if((changed = memcmp(&spindle_settings, &settings.spindle, sizeof(spindle_settings_t))) != 0)
+    if((base_changed = memcmp(&spindle_settings, &settings.spindle, sizeof(spindle_settings_t))) != 0)
         memcpy(&spindle_settings, &settings.spindle, sizeof(spindle_settings_t));
 
-    return changed;
+    if((pwm_changed = memcmp(&spindle_pwm_settings, &settings.pwm_spindle, sizeof(spindle_pwm_settings_t))) != 0)
+        memcpy(&spindle_pwm_settings, &settings.pwm_spindle, sizeof(spindle_pwm_settings_t));
+
+    return base_changed || pwm_changed;
 }
 
 // A helper method to set settings from command line
diff --git a/spindle_control.c b/spindle_control.c
index 6a53142..57936bc 100644
--- a/spindle_control.c
+++ b/spindle_control.c
@@ -831,10 +831,6 @@ bool spindle_precompute_pwm_values (spindle_ptrs_t *spindle, spindle_pwm_t *pwm_
         pwm_data->compute_value = compute_dummy_pwm_value;
     }
 
-    pwm_data->flags.invert_pwm = pwm_data->flags.invert_pwm;
-    pwm_data->flags.always_on = pwm_data->flags.always_on;
-    pwm_data->flags.cloned = pwm_data->flags.cloned;
-
     spindle->context.pwm = pwm_data;
 
 #if ENABLE_SPINDLE_LINEARIZATION
diff --git a/system.h b/system.h
index 3ba90bf..f04d98f 100644
--- a/system.h
+++ b/system.h
@@ -135,8 +135,9 @@ typedef union {
 
 // NOTE: the pin_function_t enum must be kept in sync with any changes!
 typedef union {
-    uint16_t value;
+    uint16_t bits;
     uint16_t mask;
+    uint16_t value;
     struct {
         uint16_t reset              :1,
                  feed_hold          :1,