diff --git a/Marlin/Conditionals_post.h b/Marlin/Conditionals_post.h
index a4ae28ff34..9fcd944ac0 100644
--- a/Marlin/Conditionals_post.h
+++ b/Marlin/Conditionals_post.h
@@ -788,6 +788,12 @@
     #define MAX_PROBE_X ( DELTA_PRINTABLE_RADIUS)
     #define MIN_PROBE_Y (-DELTA_PRINTABLE_RADIUS)
     #define MAX_PROBE_Y ( DELTA_PRINTABLE_RADIUS)
+  #elif IS_SCARA
+    #define SCARA_PRINTABLE_RADIUS (SCARA_LINKAGE_1 + SCARA_LINKAGE_2)
+    #define MIN_PROBE_X (-SCARA_PRINTABLE_RADIUS)
+    #define MAX_PROBE_X ( SCARA_PRINTABLE_RADIUS)
+    #define MIN_PROBE_Y (-SCARA_PRINTABLE_RADIUS)
+    #define MAX_PROBE_Y ( SCARA_PRINTABLE_RADIUS)
   #else
     // Boundaries for probing based on set limits
     #define MIN_PROBE_X (max(X_MIN_POS, X_MIN_POS + X_PROBE_OFFSET_FROM_EXTRUDER))
diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index 6547cc1522..a5c42c5f6b 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -7678,6 +7678,10 @@ inline void gcode_M205() {
 
   /**
    * M206: Set Additional Homing Offset (X Y Z). SCARA aliases T=X, P=Y
+   *
+   * *** @thinkyhead: I recommend deprecating M206 for SCARA in favor of M665.
+   * ***              M206 for SCARA will remain enabled in 1.1.x for compatibility.
+   * ***              In the next 1.2 release, it will simply be disabled by default.
    */
   inline void gcode_M206() {
     LOOP_XYZ(i)
@@ -7757,6 +7761,44 @@ inline void gcode_M205() {
     LOOP_XYZ(i) endstop_adj[i] -= z_temp;
   }
 
+#elif IS_SCARA
+
+  /**
+   * M665: Set SCARA settings
+   *
+   * Parameters:
+   *
+   *   S[segments-per-second] - Segments-per-second
+   *   P[theta-psi-offset]    - Theta-Psi offset, added to the shoulder (A/X) angle
+   *   T[theta-offset]        - Theta     offset, added to the elbow    (B/Y) angle
+   *
+   *   A, P, and X are all aliases for the shoulder angle
+   *   B, T, and Y are all aliases for the elbow angle
+   */
+  inline void gcode_M665() {
+    if (parser.seen('S')) delta_segments_per_second = parser.value_float();
+
+    const bool hasA = parser.seen('A'), hasP = parser.seen('P'), hasX = parser.seen('X');
+    const uint8_t sumAPX = hasA + hasP + hasX;
+    if (sumAPX == 1)
+      home_offset[A_AXIS] = parser.value_float();
+    else if (sumAPX > 1) {
+      SERIAL_ERROR_START;
+      SERIAL_ERRORLNPGM("Only one of A, P, or X is allowed.");
+      return;
+    }
+
+    const bool hasB = parser.seen('B'), hasT = parser.seen('T'), hasY = parser.seen('Y');
+    const uint8_t sumBTY = hasB + hasT + hasY;
+    if (sumBTY == 1)
+      home_offset[B_AXIS] = parser.value_float();
+    else if (sumBTY > 1) {
+      SERIAL_ERROR_START;
+      SERIAL_ERRORLNPGM("Only one of B, T, or Y is allowed.");
+      return;
+    }
+  }
+
 #elif ENABLED(Z_DUAL_ENDSTOPS) // !DELTA && ENABLED(Z_DUAL_ENDSTOPS)
 
   /**
@@ -11193,8 +11235,12 @@ void set_current_from_steppers_for_axis(const AxisEnum axis) {
     if (!position_is_reachable_xy(ltarget[X_AXIS], ltarget[Y_AXIS])) return true;
 
     // Get the cartesian distances moved in XYZE
-    float difference[XYZE];
-    LOOP_XYZE(i) difference[i] = ltarget[i] - current_position[i];
+    const float difference[XYZE] = {
+      ltarget[X_AXIS] - current_position[X_AXIS],
+      ltarget[Y_AXIS] - current_position[Y_AXIS],
+      ltarget[Z_AXIS] - current_position[Z_AXIS],
+      ltarget[E_AXIS] - current_position[E_AXIS]
+    };
 
     // Get the linear distance in XYZ
     float cartesian_mm = sqrt(sq(difference[X_AXIS]) + sq(difference[Y_AXIS]) + sq(difference[Z_AXIS]));
diff --git a/Marlin/configuration_store.cpp b/Marlin/configuration_store.cpp
index f23ee7770d..2d2a225793 100644
--- a/Marlin/configuration_store.cpp
+++ b/Marlin/configuration_store.cpp
@@ -1461,7 +1461,7 @@ void MarlinSettings::reset() {
     #endif
     SERIAL_EOL;
     #if ENABLED(DISTINCT_E_FACTORS)
-      SERIAL_ECHO_START;
+      CONFIG_ECHO_START;
       for (uint8_t i = 0; i < E_STEPPERS; i++) {
         SERIAL_ECHOPAIR("  M201 T", (int)i);
         SERIAL_ECHOLNPAIR(" E", VOLUMETRIC_UNIT(planner.max_acceleration_mm_per_s2[E_AXIS + i]));
diff --git a/Marlin/pins_MEGATRONICS_3.h b/Marlin/pins_MEGATRONICS_3.h
index aa6c40374f..5e4ca4b586 100644
--- a/Marlin/pins_MEGATRONICS_3.h
+++ b/Marlin/pins_MEGATRONICS_3.h
@@ -143,11 +143,14 @@
 #define BTN_ENC            33
 
 #if ENABLED(REPRAPWORLD_GRAPHICAL_LCD)
+
   #define LCD_PINS_RS      56 // CS chip select / SS chip slave select
   #define LCD_PINS_ENABLE  51 // SID (MOSI)
   #define LCD_PINS_D4      52 // SCK (CLK) clock
   #define SD_DETECT_PIN    35
+
 #else
+
   #define LCD_PINS_RS      32
   #define LCD_PINS_ENABLE  31
   #define LCD_PINS_D4      14
@@ -171,23 +174,23 @@
 //
 // M3/M4/M5 - Spindle/Laser Control
 //
-#if DISABLED(REPRAPWORLD_KEYPAD)     // try to use the keypad connector first
-  #define SPINDLE_LASER_PWM_PIN         44  // MUST BE HARDWARE PWM
-  #define SPINDLE_LASER_ENABLE_PIN      43  // Pin should have a pullup!
-  #define SPINDLE_DIR_PIN               42
+#if DISABLED(REPRAPWORLD_KEYPAD)       // try to use the keypad connector first
+  #define SPINDLE_LASER_PWM_PIN    44  // MUST BE HARDWARE PWM
+  #define SPINDLE_LASER_ENABLE_PIN 43  // Pin should have a pullup!
+  #define SPINDLE_DIR_PIN          42
 #elif EXTRUDERS <= 2
-  // try to hijack the last extruder so that we can get the PWM signal off the Y breakout
-  // move all the Y signals to the E2 extruder socket - makes dual Y steppers harder
-  #undef Y_ENABLE_PIN
-  #undef Y_STEP_PIN
-  #undef Y_DIR_PIN
-  #undef E2_STEP_PIN
-  #undef E2_ENABLE_PIN
-  #undef E2_DIR_PIN
-  #define Y_ENABLE_PIN          23
-  #define Y_STEP_PIN            22
-  #define Y_DIR_PIN             60
-  #define SPINDLE_LASER_PWM_PIN          4  // MUST BE HARDWARE PWM
-  #define SPINDLE_LASER_ENABLE_PIN      17  // Pin should have a pullup!
-  #define SPINDLE_DIR_PIN                5
+  // Hijack the last extruder so that we can get the PWM signal off the Y breakout
+  // Move Y to the E2 plug. This makes dual Y steppers harder
+  #undef Y_ENABLE_PIN  //  4
+  #undef Y_STEP_PIN    //  5
+  #undef Y_DIR_PIN     // 17
+  #undef E2_ENABLE_PIN // 23
+  #undef E2_STEP_PIN   // 22
+  #undef E2_DIR_PIN    // 60
+  #define Y_ENABLE_PIN             23
+  #define Y_STEP_PIN               22
+  #define Y_DIR_PIN                60
+  #define SPINDLE_LASER_PWM_PIN     4  // MUST BE HARDWARE PWM
+  #define SPINDLE_LASER_ENABLE_PIN 17  // Pin should have a pullup!
+  #define SPINDLE_DIR_PIN           5
 #endif
diff --git a/Marlin/pins_RAMPS.h b/Marlin/pins_RAMPS.h
index 9bd1a252c3..d1502e7d97 100644
--- a/Marlin/pins_RAMPS.h
+++ b/Marlin/pins_RAMPS.h
@@ -375,7 +375,7 @@
 //
 // M3/M4/M5 - Spindle/Laser Control
 //
-#if ENABLED(SPINDLE_LASER_ENABLE) && !PIN_EXISTS(SPINDLE_LASER_ENABLE_PIN)
+#if ENABLED(SPINDLE_LASER_ENABLE) && !PIN_EXISTS(SPINDLE_LASER_ENABLE)
   #if !defined(NUM_SERVOS) || NUM_SERVOS == 0 // try to use servo connector first
     #define SPINDLE_LASER_ENABLE_PIN  4  // Pin should have a pullup/pulldown!
     #define SPINDLE_LASER_PWM_PIN     6  // MUST BE HARDWARE PWM