diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index 03c9ba55eb..92de09eec9 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -1197,6 +1197,7 @@
 
   #define SD_MENU_CONFIRM_START             // Confirm the selected SD file before printing
 
+  //#define NO_SD_AUTOSTART                 // Remove auto#.g file support completely to save some Flash, SRAM
   //#define MENU_ADDAUTOSTART               // Add a menu option to run auto#.g files
 
   //#define BROWSE_MEDIA_ON_INSERT          // Open the file browser when media is inserted
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index 51a13389b1..9a1852d94d 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -212,3 +212,11 @@ inline void HAL_reboot() {}  // reboot the board or restart the bootloader
 #ifndef strcmp_P
   #define strcmp_P(a, b) strcmp((a), (b))
 #endif
+
+#ifndef strcat_P
+  #define strcat_P(a, b) strcat((a), (b))
+#endif
+
+#ifndef strcpy_P
+  #define strcpy_P(a, b) strcpy((a), (b))
+#endif
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index d8bba774e9..2c852f22e1 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -110,7 +110,7 @@
     #error "LCD_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
   #endif
 
-  #define SERIAL_GET_TX_BUFFER_FREE LCD_SERIAL.availableForWrite
+  #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
 #endif
 
 // Set interrupt grouping for this MCU
diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index d615f19370..0171690d4e 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -77,6 +77,10 @@
   #include "lcd/dwin/e3v2/rotary_encoder.h"
 #endif
 
+#if ENABLED(EXTENSIBLE_UI)
+  #include "lcd/extui/ui_api.h"
+#endif
+
 #if HAS_ETHERNET
   #include "feature/ethernet.h"
 #endif
@@ -360,6 +364,8 @@ void enable_all_steppers() {
   ENABLE_AXIS_Y();
   ENABLE_AXIS_Z();
   enable_e_steppers();
+
+  TERN_(EXTENSIBLE_UI, ExtUI::onSteppersEnabled());
 }
 
 void disable_e_steppers() {
@@ -379,6 +385,8 @@ void disable_all_steppers() {
   DISABLE_AXIS_Y();
   DISABLE_AXIS_Z();
   disable_e_steppers();
+
+  TERN_(EXTENSIBLE_UI, ExtUI::onSteppersDisabled());
 }
 
 #if ENABLED(G29_RETRY_AND_RECOVER)
@@ -452,6 +460,7 @@ void startOrResumeJob() {
 #if ENABLED(SDSUPPORT)
 
   inline void abortSDPrinting() {
+    IF_DISABLED(NO_SD_AUTOSTART, card.autofile_cancel());
     card.endFilePrint(TERN_(SD_RESORT, true));
     queue.clear();
     quickstop_stepper();
@@ -577,7 +586,7 @@ inline void manage_inactivity(const bool ignore_stepper_queue=false) {
       if (ELAPSED(ms, next_home_key_ms)) {
         next_home_key_ms = ms + HOME_DEBOUNCE_DELAY;
         LCD_MESSAGEPGM(MSG_AUTO_HOME);
-        queue.enqueue_now_P(G28_STR);
+        queue.inject_P(G28_STR);
       }
     }
   #endif
@@ -701,6 +710,10 @@ inline void manage_inactivity(const bool ignore_stepper_queue=false) {
  *  - Handle Joystick jogging
  */
 void idle(TERN_(ADVANCED_PAUSE_FEATURE, bool no_stepper_sleep/*=false*/)) {
+  #if ENABLED(MARLIN_DEV_MODE)
+    static uint8_t idle_depth = 0;
+    if (++idle_depth > 5) SERIAL_ECHOLNPAIR("idle() call depth: ", int(idle_depth));
+  #endif
 
   // Core Marlin activities
   manage_inactivity(TERN_(ADVANCED_PAUSE_FEATURE, no_stepper_sleep));
@@ -712,7 +725,7 @@ void idle(TERN_(ADVANCED_PAUSE_FEATURE, bool no_stepper_sleep/*=false*/)) {
   TERN_(MAX7219_DEBUG, max7219.idle_tasks());
 
   // Return if setup() isn't completed
-  if (marlin_state == MF_INITIALIZING) return;
+  if (marlin_state == MF_INITIALIZING) goto IDLE_DONE;
 
   // Handle filament runout sensors
   TERN_(HAS_FILAMENT_SENSOR, runout.run());
@@ -756,6 +769,7 @@ void idle(TERN_(ADVANCED_PAUSE_FEATURE, bool no_stepper_sleep/*=false*/)) {
 
   // Run i2c Position Encoders
   #if ENABLED(I2C_POSITION_ENCODERS)
+  {
     static millis_t i2cpem_next_update_ms;
     if (planner.has_blocks_queued()) {
       const millis_t ms = millis();
@@ -764,6 +778,7 @@ void idle(TERN_(ADVANCED_PAUSE_FEATURE, bool no_stepper_sleep/*=false*/)) {
         i2cpem_next_update_ms = ms + I2CPE_MIN_UPD_TIME_MS;
       }
     }
+  }
   #endif
 
   // Auto-report Temperatures / SD Status
@@ -785,6 +800,10 @@ void idle(TERN_(ADVANCED_PAUSE_FEATURE, bool no_stepper_sleep/*=false*/)) {
 
   // Update the LVGL interface
   TERN_(HAS_TFT_LVGL_UI, LV_TASK_HANDLER());
+
+  IDLE_DONE:
+  TERN_(MARLIN_DEV_MODE, idle_depth--);
+  return;
 }
 
 /**
@@ -1336,7 +1355,6 @@ void loop() {
     idle();
 
     #if ENABLED(SDSUPPORT)
-      card.checkautostart();
       if (card.flag.abort_sd_printing) abortSDPrinting();
       if (marlin_state == MF_SD_COMPLETE) finishSDPrinting();
     #endif
diff --git a/Marlin/src/feature/bedlevel/ubl/ubl_G29.cpp b/Marlin/src/feature/bedlevel/ubl/ubl_G29.cpp
index 9ab7861a01..11bea18c81 100644
--- a/Marlin/src/feature/bedlevel/ubl/ubl_G29.cpp
+++ b/Marlin/src/feature/bedlevel/ubl/ubl_G29.cpp
@@ -727,7 +727,7 @@
      * Probe all invalidated locations of the mesh that can be reached by the probe.
      * This attempts to fill in locations closest to the nozzle's start location first.
      */
-    void unified_bed_leveling::probe_entire_mesh(const xy_pos_t &pos, const bool do_ubl_mesh_map, const bool stow_probe, const bool do_furthest) {
+    void unified_bed_leveling::probe_entire_mesh(const xy_pos_t &nearby, const bool do_ubl_mesh_map, const bool stow_probe, const bool do_furthest) {
       probe.deploy(); // Deploy before ui.capture() to allow for PAUSE_BEFORE_DEPLOY_STOW
 
       TERN_(HAS_LCD_MENU, ui.capture());
@@ -758,7 +758,7 @@
 
         best = do_furthest
           ? find_furthest_invalid_mesh_point()
-          : find_closest_mesh_point_of_type(INVALID, pos, true);
+          : find_closest_mesh_point_of_type(INVALID, nearby, true);
 
         if (best.pos.x >= 0) {    // mesh point found and is reachable by probe
           TERN_(EXTENSIBLE_UI, ExtUI::onMeshUpdate(best.pos, ExtUI::PROBE_START));
@@ -788,8 +788,8 @@
       restore_ubl_active_state_and_leave();
 
       do_blocking_move_to_xy(
-        constrain(pos.x - probe.offset_xy.x, MESH_MIN_X, MESH_MAX_X),
-        constrain(pos.y - probe.offset_xy.y, MESH_MIN_Y, MESH_MAX_Y)
+        constrain(nearby.x - probe.offset_xy.x, MESH_MIN_X, MESH_MAX_X),
+        constrain(nearby.y - probe.offset_xy.y, MESH_MIN_Y, MESH_MAX_Y)
       );
     }
 
@@ -1206,7 +1206,7 @@
 
       found_a_NAN = true;
 
-      xy_int8_t near_pos { -1, -1 };
+      xy_int8_t nearby { -1, -1 };
       float d1, d2 = 99999.9f;
       GRID_LOOP(k, l) {
         if (isnan(z_values[k][l])) continue;
@@ -1221,7 +1221,7 @@
 
         if (d1 < d2) {    // Invalid mesh point (i,j) is closer to the defined point (k,l)
           d2 = d1;
-          near_pos.set(i, j);
+          nearby.set(i, j);
         }
       }
 
@@ -1229,8 +1229,8 @@
       // At this point d2 should have the near defined mesh point to invalid mesh point (i,j)
       //
 
-      if (found_a_real && near_pos.x >= 0 && d2 > farthest.distance) {
-        farthest.pos = near_pos; // Found an invalid location farther from the defined mesh point
+      if (found_a_real && nearby.x >= 0 && d2 > farthest.distance) {
+        farthest.pos = nearby; // Found an invalid location farther from the defined mesh point
         farthest.distance = d2;
       }
     } // GRID_LOOP
diff --git a/Marlin/src/feature/powerloss.h b/Marlin/src/feature/powerloss.h
index f964f12294..25581e1723 100644
--- a/Marlin/src/feature/powerloss.h
+++ b/Marlin/src/feature/powerloss.h
@@ -152,7 +152,7 @@ class PrintJobRecovery {
     static void resume();
     static void purge();
 
-    static inline void cancel() { purge(); card.autostart_index = 0; }
+    static inline void cancel() { purge(); IF_DISABLED(NO_SD_AUTOSTART, card.autofile_begin()); }
 
     static void load();
     static void save(const bool force=ENABLED(SAVE_EACH_CMD_MODE), const float zraise=0);
diff --git a/Marlin/src/gcode/bedlevel/abl/G29.cpp b/Marlin/src/gcode/bedlevel/abl/G29.cpp
index 9999d92e22..15555d5f8d 100644
--- a/Marlin/src/gcode/bedlevel/abl/G29.cpp
+++ b/Marlin/src/gcode/bedlevel/abl/G29.cpp
@@ -177,6 +177,8 @@ G29_TYPE GcodeSuite::G29() {
     if (DISABLED(PROBE_MANUALLY) && seenQ) G29_RETURN(false);
   #endif
 
+  TERN_(EXTENSIBLE_UI, ExtUI::onMeshLevelingStart());
+
   const bool seenA = TERN0(PROBE_MANUALLY, parser.seen('A')),
          no_action = seenA || seenQ,
               faux = ENABLED(DEBUG_LEVELING_FEATURE) && DISABLED(PROBE_MANUALLY) ? parser.boolval('C') : no_action;
@@ -392,6 +394,11 @@ G29_TYPE GcodeSuite::G29() {
 
     planner.synchronize();
 
+    #if ENABLED(AUTO_BED_LEVELING_3POINT)
+      if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("> 3-point Leveling");
+      points[0].z = points[1].z = points[2].z = 0;  // Probe at 3 arbitrary points
+    #endif
+
     if (!faux) remember_feedrate_scaling_off();
 
     // Disable auto bed leveling during G29.
@@ -409,7 +416,6 @@ G29_TYPE GcodeSuite::G29() {
     #endif
 
     #if ENABLED(AUTO_BED_LEVELING_BILINEAR)
-
       if (TERN1(PROBE_MANUALLY, !no_action)
         && (gridSpacing != bilinear_grid_spacing || probe_position_lf != bilinear_start)
       ) {
@@ -423,18 +429,8 @@ G29_TYPE GcodeSuite::G29() {
         // Can't re-enable (on error) until the new grid is written
         abl_should_enable = false;
       }
-
     #endif // AUTO_BED_LEVELING_BILINEAR
 
-    #if ENABLED(AUTO_BED_LEVELING_3POINT)
-
-      if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("> 3-point Leveling");
-
-      // Probe at 3 arbitrary points
-      points[0].z = points[1].z = points[2].z = 0;
-
-    #endif // AUTO_BED_LEVELING_3POINT
-
   } // !g29_in_progress
 
   #if ENABLED(PROBE_MANUALLY)
diff --git a/Marlin/src/gcode/calibrate/G28.cpp b/Marlin/src/gcode/calibrate/G28.cpp
index c17d6dcc8b..f54b2fb7d4 100644
--- a/Marlin/src/gcode/calibrate/G28.cpp
+++ b/Marlin/src/gcode/calibrate/G28.cpp
@@ -50,6 +50,10 @@
   #include "../../lcd/dwin/e3v2/dwin.h"
 #endif
 
+#if ENABLED(EXTENSIBLE_UI)
+  #include "../../lcd/extui/ui_api.h"
+#endif
+
 #if HAS_L64XX                         // set L6470 absolute position registers to counts
   #include "../../libs/L64XX/L64XX_Marlin.h"
 #endif
@@ -207,8 +211,6 @@ void GcodeSuite::G28() {
 
   TERN_(LASER_MOVE_G28_OFF, cutter.set_inline_enabled(false));  // turn off laser
 
-  TERN_(DWIN_CREALITY_LCD, HMI_flag.home_flag = true);
-
   #if ENABLED(DUAL_X_CARRIAGE)
     bool IDEX_saved_duplication_state = extruder_duplication_enabled;
     DualXMode IDEX_saved_mode = dual_x_carriage_mode;
@@ -230,17 +232,17 @@ void GcodeSuite::G28() {
     return;
   }
 
+  TERN_(DWIN_CREALITY_LCD, DWIN_StartHoming());
+  TERN_(EXTENSIBLE_UI, ExtUI::onHomingStart());
+
   planner.synchronize();          // Wait for planner moves to finish!
 
   SET_SOFT_ENDSTOP_LOOSE(false);  // Reset a leftover 'loose' motion state
 
   // Disable the leveling matrix before homing
   #if HAS_LEVELING
-
-    // Cancel the active G29 session
-    TERN_(PROBE_MANUALLY, g29_in_progress = false);
-
     TERN_(RESTORE_LEVELING_AFTER_G28, const bool leveling_was_active = planner.leveling_active);
+    TERN_(PROBE_MANUALLY, g29_in_progress = false);  // Cancel the active G29 session
     set_bed_leveling_enabled(false);
   #endif
 
@@ -461,6 +463,7 @@ void GcodeSuite::G28() {
   ui.refresh();
 
   TERN_(DWIN_CREALITY_LCD, DWIN_CompletedHoming());
+  TERN_(EXTENSIBLE_UI, ExtUI::onHomingComplete());
 
   report_current_position();
 
diff --git a/Marlin/src/gcode/sd/M1001.cpp b/Marlin/src/gcode/sd/M1001.cpp
index 4a461170bc..406cd074c3 100644
--- a/Marlin/src/gcode/sd/M1001.cpp
+++ b/Marlin/src/gcode/sd/M1001.cpp
@@ -27,6 +27,10 @@
 #include "../gcode.h"
 #include "../../module/printcounter.h"
 
+#if DISABLED(NO_SD_AUTOSTART)
+  #include "../../sd/cardreader.h"
+#endif
+
 #ifdef SD_FINISHED_RELEASECOMMAND
   #include "../queue.h"
 #endif
@@ -60,6 +64,11 @@
  * M1001: Execute actions for SD print completion
  */
 void GcodeSuite::M1001() {
+  // If there's another auto#.g file to run...
+  if (TERN(NO_SD_AUTOSTART, false, card.autofile_check())) return;
+
+  // Purge the recovery file...
+  TERN_(POWER_LOSS_RECOVERY, recovery.purge());
 
   // Report total print time
   const bool long_print = print_job_timer.duration() > 60;
@@ -71,9 +80,6 @@ void GcodeSuite::M1001() {
   // Set the progress bar "done" state
   TERN_(LCD_SET_PROGRESS_MANUALLY, ui.set_progress_done());
 
-  // Purge the recovery file
-  TERN_(POWER_LOSS_RECOVERY, recovery.purge());
-
   // Announce SD file completion
   {
     PORT_REDIRECT(SERIAL_BOTH);
@@ -93,9 +99,11 @@ void GcodeSuite::M1001() {
 
   // Inject SD_FINISHED_RELEASECOMMAND, if any
   #ifdef SD_FINISHED_RELEASECOMMAND
-    queue.inject_P(PSTR(SD_FINISHED_RELEASECOMMAND));
+    gcode.process_subcommands_now_P(PSTR(SD_FINISHED_RELEASECOMMAND));
   #endif
 
+  TERN_(EXTENSIBLE_UI, ExtUI::onPrintFinished());
+
   // Re-select the last printed file in the UI
   TERN_(SD_REPRINT_LAST_SELECTED_FILE, ui.reselect_last_file());
 }
diff --git a/Marlin/src/inc/Conditionals_adv.h b/Marlin/src/inc/Conditionals_adv.h
index 1bd9dc47a4..f99e363d7b 100644
--- a/Marlin/src/inc/Conditionals_adv.h
+++ b/Marlin/src/inc/Conditionals_adv.h
@@ -142,6 +142,10 @@
   #undef SD_FINISHED_RELEASECOMMAND
 #endif
 
+#if ENABLED(NO_SD_AUTOSTART)
+  #undef MENU_ADDAUTOSTART
+#endif
+
 #if EITHER(SDSUPPORT, LCD_SET_PROGRESS_MANUALLY)
   #define HAS_PRINT_PROGRESS 1
 #endif
diff --git a/Marlin/src/inc/Version.h b/Marlin/src/inc/Version.h
index 7796c4e066..b66f4dadd9 100644
--- a/Marlin/src/inc/Version.h
+++ b/Marlin/src/inc/Version.h
@@ -42,7 +42,7 @@
  * version was tagged.
  */
 #ifndef STRING_DISTRIBUTION_DATE
-  #define STRING_DISTRIBUTION_DATE "2020-12-05"
+  #define STRING_DISTRIBUTION_DATE "2020-12-07"
 #endif
 
 /**
diff --git a/Marlin/src/lcd/dwin/e3v2/dwin.h b/Marlin/src/lcd/dwin/e3v2/dwin.h
index 5bff2e9f78..8f17c30609 100644
--- a/Marlin/src/lcd/dwin/e3v2/dwin.h
+++ b/Marlin/src/lcd/dwin/e3v2/dwin.h
@@ -369,5 +369,7 @@ void DWIN_Update();
 void EachMomentUpdate();
 void DWIN_HandleScreen();
 
+inline void DWIN_StartHoming() { HMI_flag.home_flag = true; }
+
 void DWIN_CompletedHoming();
 void DWIN_CompletedLeveling();
diff --git a/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp b/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
index a7f9a7a0c3..06baa4c19d 100644
--- a/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
+++ b/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
@@ -62,6 +62,10 @@ namespace ExtUI {
   void onUserConfirmRequired(const char * const msg) { Chiron.ConfirmationRequest(msg);     }
   void onStatusChanged(const char * const msg)       { Chiron.StatusChange(msg);            }
 
+  void onHomingStart() {}
+  void onHomingComplete() {}
+  void onPrintFinished() {}
+
   void onFactoryReset() {}
 
   void onStoreSettings(char *buff) {
@@ -95,6 +99,8 @@ namespace ExtUI {
   }
 
   #if HAS_MESH
+    void onMeshLevelingStart() {}
+
     void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) {
       // Called when any mesh points are updated
       //SERIAL_ECHOLNPAIR("onMeshUpdate() x:", xpos, " y:", ypos, " z:", zval);
@@ -116,6 +122,9 @@ namespace ExtUI {
       // Called for temperature PID tuning result
     }
   #endif
+
+  void onSteppersDisabled() {}
+  void onSteppersEnabled()  {}
 }
 
 #endif // ANYCUBIC_LCD_CHIRON
diff --git a/Marlin/src/lcd/extui/anycubic_i3mega_lcd.cpp b/Marlin/src/lcd/extui/anycubic_i3mega_lcd.cpp
index 15526d16fc..e2bd96068c 100644
--- a/Marlin/src/lcd/extui/anycubic_i3mega_lcd.cpp
+++ b/Marlin/src/lcd/extui/anycubic_i3mega_lcd.cpp
@@ -52,6 +52,11 @@ namespace ExtUI {
   void onFilamentRunout(const extruder_t extruder)   { AnycubicTFT.OnFilamentRunout(); }
   void onUserConfirmRequired(const char * const msg) { AnycubicTFT.OnUserConfirmRequired(msg); }
   void onStatusChanged(const char * const msg) {}
+
+  void onHomingStart() {}
+  void onHomingComplete() {}
+  void onPrintFinished() {}
+
   void onFactoryReset() {}
 
   void onStoreSettings(char *buff) {
@@ -84,9 +89,14 @@ namespace ExtUI {
     // whether successful or not.
   }
 
-  void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) {
-    // Called when any mesh points are updated
-  }
+  #if HAS_MESH
+
+    void onMeshLevelingStart() {}
+
+    void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) {
+      // Called when any mesh points are updated
+    }
+  #endif
 
   #if ENABLED(POWER_LOSS_RECOVERY)
     void onPowerLossResume() {
@@ -99,6 +109,9 @@ namespace ExtUI {
       // Called for temperature PID tuning result
     }
   #endif
+
+  void onSteppersDisabled() {}
+  void onSteppersEnabled()  {}
 }
 
 #endif // ANYCUBIC_LCD_I3MEGA
diff --git a/Marlin/src/lcd/extui/dgus_lcd.cpp b/Marlin/src/lcd/extui/dgus_lcd.cpp
index d175b5acac..33d8bd4d89 100644
--- a/Marlin/src/lcd/extui/dgus_lcd.cpp
+++ b/Marlin/src/lcd/extui/dgus_lcd.cpp
@@ -76,7 +76,12 @@ namespace ExtUI {
 
   void onStatusChanged(const char * const msg) { ScreenHandler.setstatusmessage(msg); }
 
+  void onHomingStart() {}
+  void onHomingComplete() {}
+  void onPrintFinished() {}
+
   void onFactoryReset() {}
+
   void onStoreSettings(char *buff) {
     // Called when saving to EEPROM (i.e. M500). If the ExtUI needs
     // permanent data to be stored, it can write up to eeprom_data_size bytes
@@ -108,6 +113,8 @@ namespace ExtUI {
   }
 
   #if HAS_MESH
+    void onMeshLevelingStart() {}
+
     void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) {
       // Called when any mesh points are updated
     }
@@ -146,5 +153,8 @@ namespace ExtUI {
     }
   #endif
 
+  void onSteppersDisabled() {}
+  void onSteppersEnabled()  {}
 }
+
 #endif // HAS_DGUS_LCD
diff --git a/Marlin/src/lcd/extui/example.cpp b/Marlin/src/lcd/extui/example.cpp
index 592d67214d..dd4b3312eb 100644
--- a/Marlin/src/lcd/extui/example.cpp
+++ b/Marlin/src/lcd/extui/example.cpp
@@ -47,9 +47,9 @@ namespace ExtUI {
   }
   void onIdle() {}
   void onPrinterKilled(PGM_P const error, PGM_P const component) {}
-  void onMediaInserted() {};
-  void onMediaError() {};
-  void onMediaRemoved() {};
+  void onMediaInserted() {}
+  void onMediaError() {}
+  void onMediaRemoved() {}
   void onPlayTone(const uint16_t frequency, const uint16_t duration) {}
   void onPrintTimerStarted() {}
   void onPrintTimerPaused() {}
@@ -57,6 +57,11 @@ namespace ExtUI {
   void onFilamentRunout(const extruder_t extruder) {}
   void onUserConfirmRequired(const char * const msg) {}
   void onStatusChanged(const char * const msg) {}
+
+  void onHomingStart() {}
+  void onHomingComplete() {}
+  void onPrintFinished() {}
+
   void onFactoryReset() {}
 
   void onStoreSettings(char *buff) {
@@ -90,6 +95,8 @@ namespace ExtUI {
   }
 
   #if HAS_MESH
+    void onMeshLevelingStart() {}
+
     void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) {
       // Called when any mesh points are updated
     }
@@ -110,6 +117,9 @@ namespace ExtUI {
       // Called for temperature PID tuning result
     }
   #endif
+
+  void onSteppersDisabled() {}
+  void onSteppersEnabled()  {}
 }
 
 #endif // EXTUI_EXAMPLE && EXTENSIBLE_UI
diff --git a/Marlin/src/lcd/extui/lib/ftdi_eve_touch_ui/marlin_events.cpp b/Marlin/src/lcd/extui/lib/ftdi_eve_touch_ui/marlin_events.cpp
index ed7e653af1..fc9b5d0a70 100644
--- a/Marlin/src/lcd/extui/lib/ftdi_eve_touch_ui/marlin_events.cpp
+++ b/Marlin/src/lcd/extui/lib/ftdi_eve_touch_ui/marlin_events.cpp
@@ -87,8 +87,9 @@ namespace ExtUI {
     InterfaceSoundsScreen::playEventSound(InterfaceSoundsScreen::PRINTING_FINISHED);
   }
 
-  void onPrintTimerPaused() {
-  }
+  void onPrintTimerPaused() {}
+
+  void onPrintFinished() {}
 
   void onFilamentRunout(const extruder_t extruder) {
     char lcd_msg[30];
@@ -97,6 +98,9 @@ namespace ExtUI {
     InterfaceSoundsScreen::playEventSound(InterfaceSoundsScreen::PRINTING_FAILED, FTDI::PLAY_SYNCHRONOUS);
   }
 
+  void onHomingStart() {}
+  void onHomingComplete() {}
+
   void onFactoryReset() {
     InterfaceSettingsScreen::defaultSettings();
   }
@@ -134,6 +138,8 @@ namespace ExtUI {
   }
 
   #if HAS_LEVELING && HAS_MESH
+    void onMeshLevelingStart() {}
+
     void onMeshUpdate(const int8_t x, const int8_t y, const float val) {
       BedMeshScreen::onMeshUpdate(x, y, val);
     }
@@ -170,6 +176,9 @@ namespace ExtUI {
       GOTO_SCREEN(StatusScreen);
     }
   #endif // HAS_PID_HEATING
+
+  void onSteppersDisabled() {}
+  void onSteppersEnabled()  {}
 }
 
 #endif // TOUCH_UI_FTDI_EVE
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index 5505a0dff7..bdbf3802ab 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -511,12 +511,15 @@ namespace ExtUI {
 
   // Not needed for Malyan LCD
   void onStatusChanged(const char * const) {}
-  void onMediaInserted() {};
-  void onMediaError() {};
-  void onMediaRemoved() {};
+  void onMediaInserted() {}
+  void onMediaError() {}
+  void onMediaRemoved() {}
   void onPlayTone(const uint16_t, const uint16_t) {}
   void onFilamentRunout(const extruder_t extruder) {}
   void onUserConfirmRequired(const char * const) {}
+  void onHomingStart() {}
+  void onHomingComplete() {}
+  void onPrintFinished() {}
   void onFactoryReset() {}
   void onStoreSettings(char*) {}
   void onLoadSettings(const char*) {}
@@ -524,6 +527,7 @@ namespace ExtUI {
   void onConfigurationStoreRead(bool) {}
 
   #if HAS_MESH
+    void onMeshLevelingStart() {}
     void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval) {}
     void onMeshUpdate(const int8_t xpos, const int8_t ypos, const ExtUI::probe_state_t state) {}
   #endif
@@ -531,6 +535,9 @@ namespace ExtUI {
   #if ENABLED(POWER_LOSS_RECOVERY)
     void onPowerLossResume() {}
   #endif
+
+  void onSteppersDisabled() {}
+  void onSteppersEnabled()  {}
 }
 
 #endif // MALYAN_LCD
diff --git a/Marlin/src/lcd/extui/ui_api.h b/Marlin/src/lcd/extui/ui_api.h
index c429a0aade..cdf9b4412a 100644
--- a/Marlin/src/lcd/extui/ui_api.h
+++ b/Marlin/src/lcd/extui/ui_api.h
@@ -140,6 +140,7 @@ namespace ExtUI {
       bed_mesh_t& getMeshArray();
       float getMeshPoint(const xy_uint8_t &pos);
       void setMeshPoint(const xy_uint8_t &pos, const float zval);
+      void onMeshLevelingStart();
       void onMeshUpdate(const int8_t xpos, const int8_t ypos, const float zval);
       inline void onMeshUpdate(const xy_int8_t &pos, const float zval) { onMeshUpdate(pos.x, pos.y, zval); }
 
@@ -344,11 +345,16 @@ namespace ExtUI {
   void onPrintTimerStarted();
   void onPrintTimerPaused();
   void onPrintTimerStopped();
+  void onPrintFinished();
   void onFilamentRunout(const extruder_t extruder);
   void onUserConfirmRequired(const char * const msg);
   void onUserConfirmRequired_P(PGM_P const pstr);
   void onStatusChanged(const char * const msg);
   void onStatusChanged_P(PGM_P const pstr);
+  void onHomingStart();
+  void onHomingComplete();
+  void onSteppersDisabled();
+  void onSteppersEnabled();
   void onFactoryReset();
   void onStoreSettings(char *);
   void onLoadSettings(const char *);
diff --git a/Marlin/src/lcd/language/language_en.h b/Marlin/src/lcd/language/language_en.h
index 2892f79df8..0b96403b72 100644
--- a/Marlin/src/lcd/language/language_en.h
+++ b/Marlin/src/lcd/language/language_en.h
@@ -431,9 +431,9 @@ namespace Language_en {
   PROGMEM Language_Str MSG_FILAMENTCHANGE                  = _UxGT("Change Filament");
   PROGMEM Language_Str MSG_FILAMENTCHANGE_E                = _UxGT("Change Filament *");
   PROGMEM Language_Str MSG_FILAMENTLOAD                    = _UxGT("Load Filament");
-  PROGMEM Language_Str MSG_FILAMENTLOAD_E                  = _UxGT("Load Filament *");
+  PROGMEM Language_Str MSG_FILAMENTLOAD_E                  = _UxGT("Load *");
   PROGMEM Language_Str MSG_FILAMENTUNLOAD                  = _UxGT("Unload Filament");
-  PROGMEM Language_Str MSG_FILAMENTUNLOAD_E                = _UxGT("Unload Filament *");
+  PROGMEM Language_Str MSG_FILAMENTUNLOAD_E                = _UxGT("Unload *");
   PROGMEM Language_Str MSG_FILAMENTUNLOAD_ALL              = _UxGT("Unload All");
   PROGMEM Language_Str MSG_ATTACH_MEDIA                    = _UxGT("Attach Media");
   PROGMEM Language_Str MSG_CHANGE_MEDIA                    = _UxGT("Change Media");
diff --git a/Marlin/src/lcd/menu/menu_main.cpp b/Marlin/src/lcd/menu/menu_main.cpp
index cda11bfc57..1b87e06cc8 100644
--- a/Marlin/src/lcd/menu/menu_main.cpp
+++ b/Marlin/src/lcd/menu/menu_main.cpp
@@ -136,7 +136,7 @@ void menu_main() {
       // Run Auto Files
       //
       #if ENABLED(MENU_ADDAUTOSTART)
-        ACTION_ITEM(MSG_RUN_AUTO_FILES, card.beginautostart);
+        ACTION_ITEM(MSG_RUN_AUTO_FILES, card.autofile_begin);
       #endif
 
       if (card_detected) {
@@ -238,7 +238,7 @@ void menu_main() {
       // Autostart
       //
       #if ENABLED(MENU_ADDAUTOSTART)
-        ACTION_ITEM(MSG_RUN_AUTO_FILES, card.beginautostart);
+        ACTION_ITEM(MSG_RUN_AUTO_FILES, card.autofile_begin);
       #endif
 
       if (card_detected) {
diff --git a/Marlin/src/pins/lpc1768/pins_BTT_SKR_common.h b/Marlin/src/pins/lpc1768/pins_BTT_SKR_common.h
index e6cfc0afaf..867b6b6871 100644
--- a/Marlin/src/pins/lpc1768/pins_BTT_SKR_common.h
+++ b/Marlin/src/pins/lpc1768/pins_BTT_SKR_common.h
@@ -34,7 +34,11 @@
 //#define HAS_BTT_EXP_MOT 1
 
 #if BOTH(HAS_WIRED_LCD,HAS_BTT_EXP_MOT)
-  #ERROR "Having a LCD on EXP1/EXP2 and a expanion motor module on EXP1/EXP2 is not possable."
+  #if EITHER(CR10_STOCKDISPLAY,ENDER2_STOCKDISPLAY)
+    #define EXP_MOT_USE_EXP2_ONLY
+  #else
+    #error "Having a LCD that uses both EXP1/EXP2 and a expanion motor module on EXP1/EXP2 is not possible."
+  #endif
 #endif
 
 // Ignore temp readings during development.
@@ -133,36 +137,48 @@
  * (M3DIR) 0.15 | · · | 0.17 (M3STP)           (M3RX) 0.28 | · · | 1.30 (M3DIAG)
  *               -----                                      -----
  *               EXP2                                       EXP1
+ *
+ * NB In EXP_MOT_USE_EXP2_ONLY mode EXP1 is not used and M2EN and M3EN need to be jumpered to M1EN
  */
 
   // M1 on Driver Expansion Module
   #define E2_STEP_PIN                      EXPA2_05_PIN
   #define E2_DIR_PIN                       EXPA2_06_PIN
   #define E2_ENABLE_PIN                    EXPA2_04_PIN
-  #define E2_DIAG_PIN                      EXPA1_06_PIN
-  #define E2_CS_PIN                        EXPA1_05_PIN
-  #if HAS_TMC_UART
-    #define E2_SERIAL_TX_PIN               EXPA1_05_PIN
-    #define E2_SERIAL_RX_PIN               EXPA1_05_PIN
+  #ifndef EXP_MOT_USE_EXP2_ONLY
+    #define E2_DIAG_PIN                    EXPA1_06_PIN
+    #define E2_CS_PIN                      EXPA1_05_PIN
+    #if HAS_TMC_UART
+      #define E2_SERIAL_TX_PIN             EXPA1_05_PIN
+      #define E2_SERIAL_RX_PIN             EXPA1_05_PIN
+    #endif
   #endif
   // M2 on Driver Expansion Module
   #define E3_STEP_PIN                      EXPA2_08_PIN
   #define E3_DIR_PIN                       EXPA2_07_PIN
-  #define E3_ENABLE_PIN                    EXPA1_03_PIN
-  #define E3_DIAG_PIN                      EXPA1_08_PIN
-  #define E3_CS_PIN                        EXPA1_07_PIN
-  #if HAS_TMC_UART
-    #define E3_SERIAL_TX_PIN               EXPA1_07_PIN
-    #define E3_SERIAL_RX_PIN               EXPA1_07_PIN
+  #ifndef EXP_MOT_USE_EXP2_ONLY
+    #define E3_ENABLE_PIN                  EXPA1_03_PIN
+    #define E3_DIAG_PIN                    EXPA1_08_PIN
+    #define E3_CS_PIN                      EXPA1_07_PIN
+    #if HAS_TMC_UART
+      #define E3_SERIAL_TX_PIN             EXPA1_07_PIN
+      #define E3_SERIAL_RX_PIN             EXPA1_07_PIN
+    #endif
+  #else
+    #define E3_ENABLE_PIN                  EXPA2_04_PIN
   #endif
   // M3 on Driver Expansion Module
   #define E4_STEP_PIN                      EXPA2_10_PIN
   #define E4_DIR_PIN                       EXPA2_09_PIN
-  #define E4_ENABLE_PIN                    EXPA1_04_PIN
-  #define E4_DIAG_PIN                      EXPA1_10_PIN
-  #define E4_CS_PIN                        EXPA1_09_PIN
-  #if HAS_TMC_UART
-    #define E4_SERIAL_TX_PIN               EXPA1_09_PIN
-    #define E4_SERIAL_RX_PIN               EXPA1_09_PIN
+  #ifndef EXP_MOT_USE_EXP2_ONLY
+    #define E4_ENABLE_PIN                  EXPA1_04_PIN
+    #define E4_DIAG_PIN                    EXPA1_10_PIN
+    #define E4_CS_PIN                      EXPA1_09_PIN
+    #if HAS_TMC_UART
+      #define E4_SERIAL_TX_PIN             EXPA1_09_PIN
+      #define E4_SERIAL_RX_PIN             EXPA1_09_PIN
+    #endif
+  #else
+    #define E4_ENABLE_PIN                  EXPA2_04_PIN
   #endif
 #endif // HAS_BTT_EXP_MOT
diff --git a/Marlin/src/pins/pins.h b/Marlin/src/pins/pins.h
index 1961d5cf8d..fbae5356ca 100644
--- a/Marlin/src/pins/pins.h
+++ b/Marlin/src/pins/pins.h
@@ -582,12 +582,12 @@
   #include "stm32f4/pins_VAKE403D.h"            // STM32F4
 #elif MB(FYSETC_S6)
   #include "stm32f4/pins_FYSETC_S6.h"           // STM32F4                                env:FYSETC_S6
+#elif MB(FYSETC_S6_V2_0)
+  #include "stm32f4/pins_FYSETC_S6_V2_0.h"      // STM32F4                                env:FYSETC_S6
 #elif MB(FLYF407ZG)
   #include "stm32f4/pins_FLYF407ZG.h"           // STM32F4                                env:FLYF407ZG
 #elif MB(MKS_ROBIN2)
   #include "stm32f4/pins_MKS_ROBIN2.h"          // STM32F4                                env:MKS_ROBIN2
-#elif MB(FYSETC_S6_V2_0)
-  #include "stm32f4/pins_FYSETC_S6_V2_0.h"      // STM32F4                                env:FYSETC_S6
 
 //
 // ARM Cortex M7
diff --git a/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h b/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h
index c66bca8540..a7c06cb99d 100644
--- a/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h
+++ b/Marlin/src/pins/stm32f1/pins_CREALITY_V4.h
@@ -27,7 +27,7 @@
 #if NOT_TARGET(__STM32F1__)
   #error "Oops! Select an STM32F1 board in 'Tools > Board.'"
 #elif HOTENDS > 1 || E_STEPPERS > 1
-  #error "Creality_V4 only supports one hotend / E-stepper. Comment out this line to continue."
+  #error "Creality V4 only supports one hotend / E-stepper. Comment out this line to continue."
 #endif
 
 #ifndef BOARD_INFO_NAME
diff --git a/Marlin/src/pins/stm32f1/pins_CREALITY_V452.h b/Marlin/src/pins/stm32f1/pins_CREALITY_V452.h
index 348ab28dff..715fd89db8 100644
--- a/Marlin/src/pins/stm32f1/pins_CREALITY_V452.h
+++ b/Marlin/src/pins/stm32f1/pins_CREALITY_V452.h
@@ -33,81 +33,88 @@
 #define BOARD_NAME "Creality v4.5.2"
 #define DEFAULT_MACHINE_NAME "Creality3D"
 
+//
+// Release PB4 (Z_STEP_PIN) from JTAG NRST role
+//
+#define DISABLE_DEBUG
+
 #define BOARD_NO_NATIVE_USB
 
 //
 // EEPROM
 //
 #if NO_EEPROM_SELECTED
-  #define IIC_BL24CXX_EEPROM                    // EEPROM on I2C-0
+  #define IIC_BL24CXX_EEPROM                      // EEPROM on I2C-0
   //#define SDCARD_EEPROM_EMULATION
 #endif
 
 #if ENABLED(IIC_BL24CXX_EEPROM)
-  #define IIC_EEPROM_SDA                  PA11
-  #define IIC_EEPROM_SCL                  PA12
-  #define MARLIN_EEPROM_SIZE             0x800  // 2Kb (24C16)
+  #define IIC_EEPROM_SDA                    PA11
+  #define IIC_EEPROM_SCL                    PA12
+  #define MARLIN_EEPROM_SIZE               0x800  // 2Kb (24C16)
 #elif ENABLED(SDCARD_EEPROM_EMULATION)
-  #define MARLIN_EEPROM_SIZE             0x800  // 2Kb
+  #define MARLIN_EEPROM_SIZE               0x800  // 2Kb
 #endif
 
 //
 // Limit Switches
 //
-#define X_MIN_PIN           PC4
-// #define X_MAX_PIN          PA7
-#define Y_MIN_PIN           PC5
-#define Z_MIN_PIN           PA4
-#define PROBE_TARE_PIN      PA5
+#define X_STOP_PIN                          PC4
+#define Y_STOP_PIN                          PC5
+#define Z_STOP_PIN                          PA4
+
+#define FIL_RUNOUT_PIN                      PA7
+
+//
+// Probe
+//
+#define PROBE_TARE_PIN                      PA5
+#define PROBE_ENABLE_PIN                    PC6   // Optoswitch to Enable Z Probe
 
 //
 // Steppers
 //
-#define X_ENABLE_PIN        PC3
-#define X_STEP_PIN          PB8
-#define X_DIR_PIN           PB7
+#define X_ENABLE_PIN                        PC3
+#define X_STEP_PIN                          PB8
+#define X_DIR_PIN                           PB7
 
-#define Y_ENABLE_PIN        PC3
-#define Y_STEP_PIN          PB6
-#define Y_DIR_PIN           PB5
+#define Y_ENABLE_PIN                        PC3
+#define Y_STEP_PIN                          PB6
+#define Y_DIR_PIN                           PB5
 
-#define Z_ENABLE_PIN        PC3
-#define Z_STEP_PIN          PB4
-#define Z_DIR_PIN           PB3
+#define Z_ENABLE_PIN                        PC3
+#define Z_STEP_PIN                          PB4
+#define Z_DIR_PIN                           PB3
 
-#define E0_ENABLE_PIN       PC3
-#define E0_STEP_PIN         PC2
-#define E0_DIR_PIN          PB9
-
-
-//
-// Release PB4 (Z_STEP_PIN) from JTAG NRST role
-//
-#define DISABLE_DEBUG
+#define E0_ENABLE_PIN                       PC3
+#define E0_STEP_PIN                         PC2
+#define E0_DIR_PIN                          PB9
 
 //
 // Temperature Sensors
 //
-#define TEMP_0_PIN         PB1   // TH1
-#define TEMP_BED_PIN       PB0   // TB1
+#define TEMP_0_PIN                          PB1   // TH1
+#define TEMP_BED_PIN                        PB0   // TB1
 
 //
 // Heaters / Fans
+//
+#define HEATER_0_PIN                        PA1   // HEATER1
+#define HEATER_BED_PIN                      PA2   // HOT BED
 
-#define HEATER_0_PIN       PA1   // HEATER1
-#define HEATER_BED_PIN     PA2   // HOT BED
-
-#define FAN_PIN            PA0   // FAN
+#define FAN_PIN                             PA0   // FAN
 #define FAN_SOFT_PWM
 
-/* SD card detect */
-#define SD_DETECT_PIN      PC7
-#define NO_SD_HOST_DRIVE       // SD is only seen by the printer
+//
+// SD Card
+//
+#define SD_DETECT_PIN                       PC7
+#define NO_SD_HOST_DRIVE                          // SD is only seen by the printer
 
-#define SDIO_SUPPORT           // Extra added by Creality
-#define SDIO_CLOCK     6000000 // In original source code overridden by Creality in sdio.h
+#define SDIO_SUPPORT                              // Extra added by Creality
+#define SDIO_CLOCK                       6000000  // In original source code overridden by Creality in sdio.h
 
-#define CASE_LIGHT_PIN     PA6
-
-#define FIL_RUNOUT_PIN     PA7
-#define PROBE_ENABLE_PIN   PC6 // Optoswitch to Enable Z Probe
+//
+// Misc. Functions
+//
+#define CASE_LIGHT_PIN                      PA6
diff --git a/Marlin/src/pins/stm32f4/pins_FYSETC_S6.h b/Marlin/src/pins/stm32f4/pins_FYSETC_S6.h
index a8105c37a2..decf4aeb6b 100644
--- a/Marlin/src/pins/stm32f4/pins_FYSETC_S6.h
+++ b/Marlin/src/pins/stm32f4/pins_FYSETC_S6.h
@@ -42,7 +42,6 @@
 //
 #if NO_EEPROM_SELECTED
   #define FLASH_EEPROM_EMULATION
-  //#define SRAM_EEPROM_EMULATION
   //#define I2C_EEPROM
 #endif
 
@@ -51,7 +50,7 @@
   // 128 kB sector allocated for EEPROM emulation.
   #define FLASH_EEPROM_LEVELING
 #elif ENABLED(I2C_EEPROM)
-  #define MARLIN_EEPROM_SIZE              0x1000  // 4KB
+  #define MARLIN_EEPROM_SIZE              0x0800  // 2KB
 #endif
 
 //
diff --git a/Marlin/src/pins/stm32f4/pins_FYSETC_S6_V2_0.h b/Marlin/src/pins/stm32f4/pins_FYSETC_S6_V2_0.h
index b12c12c848..641805d855 100644
--- a/Marlin/src/pins/stm32f4/pins_FYSETC_S6_V2_0.h
+++ b/Marlin/src/pins/stm32f4/pins_FYSETC_S6_V2_0.h
@@ -29,7 +29,6 @@
 #if NO_EEPROM_SELECTED
   #undef NO_EEPROM_SELECTED
   //#define FLASH_EEPROM_EMULATION
-  //#define SRAM_EEPROM_EMULATION
   #define I2C_EEPROM
 #endif
 
diff --git a/Marlin/src/sd/cardreader.cpp b/Marlin/src/sd/cardreader.cpp
index bce84bbd39..fe8bc4879a 100644
--- a/Marlin/src/sd/cardreader.cpp
+++ b/Marlin/src/sd/cardreader.cpp
@@ -61,7 +61,8 @@
 
 card_flags_t CardReader::flag;
 char CardReader::filename[FILENAME_LENGTH], CardReader::longFilename[LONG_FILENAME_LENGTH];
-int8_t CardReader::autostart_index;
+
+IF_DISABLED(NO_SD_AUTOSTART, uint8_t CardReader::autofile_index); // = 0
 
 #if BOTH(HAS_MULTI_SERIAL, BINARY_FILE_TRANSFER)
   int8_t CardReader::transfer_port_index;
@@ -135,17 +136,17 @@ CardReader::CardReader() {
       //sort_reverse = false;
     #endif
   #endif
+
   flag.sdprinting = flag.mounted = flag.saving = flag.logging = false;
   filesize = sdpos = 0;
 
   TERN_(HAS_MEDIA_SUBCALLS, file_subcall_ctr = 0);
 
+  IF_DISABLED(NO_SD_AUTOSTART, autofile_cancel());
+
   workDirDepth = 0;
   ZERO(workDirParents);
 
-  // Disable autostart until card is initialized
-  autostart_index = -1;
-
   #if ENABLED(SDSUPPORT) && PIN_EXISTS(SD_DETECT)
     SET_INPUT_PULLUP(SD_DETECT_PIN);
   #endif
@@ -442,12 +443,14 @@ void CardReader::manage_media() {
 
     if (stat) {
       TERN_(SDCARD_EEPROM_EMULATION, settings.first_load());
-      if (old_stat == 2)              // First mount?
+      if (old_stat == 2) {            // First mount?
         DEBUG_ECHOLNPGM("First mount.");
-        TERN(POWER_LOSS_RECOVERY,
-          recovery.check(),           // Check for PLR file. (If not there it will beginautostart)
-          beginautostart()            // Look for auto0.g on the next loop
-        );
+        #if ENABLED(POWER_LOSS_RECOVERY)
+          recovery.check();           // Check for PLR file. (If not there then call autofile_begin)
+        #elif DISABLED(NO_SD_AUTOSTART)
+          autofile_begin();           // Look for auto0.g on the next loop
+        #endif
+      }
     }
   }
   else
@@ -477,12 +480,12 @@ void CardReader::release() {
  * Enqueues M23 and M24 commands to initiate a media print.
  */
 void CardReader::openAndPrintFile(const char *name) {
-  char cmd[4 + strlen(name) + 1]; // Room for "M23 ", filename, and null
+  char cmd[4 + strlen(name) + 1 + 3 + 1]; // Room for "M23 ", filename, "\n", "M24", and null
   extern const char M23_STR[];
   sprintf_P(cmd, M23_STR, name);
   for (char *c = &cmd[4]; *c; c++) *c = tolower(*c);
-  queue.enqueue_one_now(cmd);
-  queue.enqueue_now_P(M24_STR);
+  strcat_P(cmd, PSTR("\nM24"));
+  queue.inject(cmd);
 }
 
 /**
@@ -511,7 +514,7 @@ void CardReader::endFilePrint(TERN_(SD_RESORT, const bool re_sort/*=false*/)) {
 
 void CardReader::openLogFile(char * const path) {
   flag.logging = DISABLED(SDCARD_READONLY);
-  TERN(SDCARD_READONLY,,openFileWrite(path));
+  IF_DISABLED(SDCARD_READONLY, openFileWrite(path));
 }
 
 //
@@ -662,14 +665,24 @@ void CardReader::openFileWrite(char * const path) {
 //
 bool CardReader::fileExists(const char * const path) {
   if (!isMounted()) return false;
+
+  DEBUG_ECHOLNPAIR("fileExists: ", path);
+
+  // Dive to the file's directory and get the base name
   SdFile *diveDir = nullptr;
   const char * const fname = diveToFile(false, diveDir, path);
-  if (fname) {
-    diveDir->rewind();
-    selectByName(*diveDir, fname);
-    //diveDir->close();
-  }
-  return !!fname;
+  if (!fname) return false;
+
+  // Get the longname of the checked file
+  //diveDir->rewind();
+  //selectByName(*diveDir, fname);
+  //diveDir->close();
+
+  // Try to open the file and return the result
+  SdFile tmpFile;
+  const bool success = tmpFile.open(diveDir, fname, O_READ);
+  if (success) tmpFile.close();
+  return success;
 }
 
 //
@@ -725,42 +738,48 @@ void CardReader::write_command(char * const buf) {
   if (file.writeError) SERIAL_ERROR_MSG(STR_SD_ERR_WRITE_TO_FILE);
 }
 
-//
-// Run the next autostart file. Called:
-// - On boot after successful card init
-// - After finishing the previous autostart file
-// - From the LCD command to run the autostart file
-//
+#if DISABLED(NO_SD_AUTOSTART)
+  /**
+   * Run all the auto#.g files. Called:
+   * - On boot after successful card init.
+   * - From the LCD command to Run Auto Files
+   */
+  void CardReader::autofile_begin() {
+    autofile_index = 1;
+    (void)autofile_check();
+  }
 
-void CardReader::checkautostart() {
+  /**
+   * Run the next auto#.g file. Called:
+   *   - On boot after successful card init
+   *   - After finishing the previous auto#.g file
+   *   - From the LCD command to begin the auto#.g files
+   *
+   * Return 'true' if there was nothing to do
+   */
+  bool CardReader::autofile_check() {
+    if (!autofile_index) return true;
 
-  if (autostart_index < 0 || flag.sdprinting) return;
+    if (!isMounted())
+      mount();
+    else if (ENABLED(SDCARD_EEPROM_EMULATION))
+      settings.first_load();
 
-  if (!isMounted()) mount();
-  TERN_(SDCARD_EEPROM_EMULATION, else settings.first_load());
-
-  // Don't run auto#.g when a PLR file exists
-  if (isMounted() && TERN1(POWER_LOSS_RECOVERY, !recovery.valid())) {
-    char autoname[8];
-    sprintf_P(autoname, PSTR("auto%c.g"), autostart_index + '0');
-    dir_t p;
-    root.rewind();
-    while (root.readDir(&p, nullptr) > 0) {
-      for (int8_t i = (int8_t)strlen((char*)p.name); i--;) p.name[i] = tolower(p.name[i]);
-      if (p.name[9] != '~' && strncmp((char*)p.name, autoname, 5) == 0) {
+    // Don't run auto#.g when a PLR file exists
+    if (isMounted() && TERN1(POWER_LOSS_RECOVERY, !recovery.valid())) {
+      char autoname[10];
+      sprintf_P(autoname, PSTR("/auto%c.g"), '0' + autofile_index - 1);
+      if (fileExists(autoname)) {
+        cdroot();
         openAndPrintFile(autoname);
-        autostart_index++;
-        return;
+        autofile_index++;
+        return false;
       }
     }
+    autofile_cancel();
+    return true;
   }
-  autostart_index = -1;
-}
-
-void CardReader::beginautostart() {
-  autostart_index = 0;
-  cdroot();
-}
+#endif
 
 void CardReader::closefile(const bool store_location/*=false*/) {
   file.sync();
@@ -1231,7 +1250,7 @@ void CardReader::fileHasFinished() {
     if (!isMounted()) return;
     if (recovery.file.isOpen()) return;
     if (!recovery.file.open(&root, recovery.filename, read ? O_READ : O_CREAT | O_WRITE | O_TRUNC | O_SYNC))
-      SERIAL_ECHOLNPAIR(STR_SD_OPEN_FILE_FAIL, recovery.filename, ".");
+      openFailed(recovery.filename);
     else if (!read)
       echo_write_to_file(recovery.filename);
   }
diff --git a/Marlin/src/sd/cardreader.h b/Marlin/src/sd/cardreader.h
index dabbf719f9..b775d8a873 100644
--- a/Marlin/src/sd/cardreader.h
+++ b/Marlin/src/sd/cardreader.h
@@ -90,10 +90,12 @@ public:
   static void openLogFile(char * const path);
   static void write_command(char * const buf);
 
-  // Auto-Start files
-  static int8_t autostart_index;                    // Index of autoX.g files
-  static void beginautostart();
-  static void checkautostart();
+  #if DISABLED(NO_SD_AUTOSTART)     // Auto-Start auto#.g file handling
+    static uint8_t autofile_index;  // Next auto#.g index to run, plus one. Ignored by autofile_check when zero.
+    static void autofile_begin();   // Begin check. Called automatically after boot-up.
+    static bool autofile_check();   // Check for the next auto-start file and run it.
+    static inline void autofile_cancel() { autofile_index = 0; }
+  #endif
 
   // Basic file ops
   static void openFileRead(char * const path, const uint8_t subcall=0);
diff --git a/buildroot/tests/mega2560-tests b/buildroot/tests/mega2560-tests
index da3a79f58c..0a17cacba1 100755
--- a/buildroot/tests/mega2560-tests
+++ b/buildroot/tests/mega2560-tests
@@ -49,7 +49,7 @@ opt_set TEMP_SENSOR_4 1000
 opt_set TEMP_SENSOR_BED 1
 opt_enable AUTO_BED_LEVELING_UBL RESTORE_LEVELING_AFTER_G28 DEBUG_LEVELING_FEATURE G26_MESH_VALIDATION ENABLE_LEVELING_FADE_HEIGHT SKEW_CORRECTION \
            REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER LIGHTWEIGHT_UI STATUS_MESSAGE_SCROLLING BOOT_MARLIN_LOGO_SMALL \
-           SDSUPPORT SDCARD_SORT_ALPHA USB_FLASH_DRIVE_SUPPORT SCROLL_LONG_FILENAMES CANCEL_OBJECTS \
+           SDSUPPORT SDCARD_SORT_ALPHA USB_FLASH_DRIVE_SUPPORT SCROLL_LONG_FILENAMES CANCEL_OBJECTS NO_SD_AUTOSTART \
            EEPROM_SETTINGS EEPROM_CHITCHAT GCODE_MACROS CUSTOM_USER_MENUS \
            MULTI_NOZZLE_DUPLICATION CLASSIC_JERK LIN_ADVANCE QUICK_HOME \
            LCD_SET_PROGRESS_MANUALLY PRINT_PROGRESS_SHOW_DECIMALS SHOW_REMAINING_TIME \
diff --git a/platformio.ini b/platformio.ini
index 0cff2dac60..237634a454 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -203,7 +203,7 @@ extra_scripts      =
   pre:buildroot/share/PlatformIO/scripts/common-dependencies.py
   pre:buildroot/share/PlatformIO/scripts/common-cxxflags.py
   post:buildroot/share/PlatformIO/scripts/common-dependencies-post.py
-build_flags        = -fmax-errors=5 -g -D__MARLIN_FIRMWARE__ -fmerge-all-constants
+build_flags        = -fmax-errors=5 -g -D__MARLIN_FIRMWARE__ -fmerge-constants
 lib_deps           =
 
 #