diff --git a/Marlin/src/gcode/gcode.h b/Marlin/src/gcode/gcode.h
index 1efcb1cf9345..a6b530a2682a 100644
--- a/Marlin/src/gcode/gcode.h
+++ b/Marlin/src/gcode/gcode.h
@@ -886,7 +886,7 @@ class GcodeSuite {
     static void M250_report(const bool forReplay=true);
   #endif
 
-  #if HAS_DISPLAY_SLEEP
+  #if HAS_GCODE_M255
     static void M255();
     static void M255_report(const bool forReplay=true);
   #endif
diff --git a/Marlin/src/gcode/lcd/M255.cpp b/Marlin/src/gcode/lcd/M255.cpp
index cfdf27b8a1fc..4a9049ab2c61 100644
--- a/Marlin/src/gcode/lcd/M255.cpp
+++ b/Marlin/src/gcode/lcd/M255.cpp
@@ -36,7 +36,7 @@ void GcodeSuite::M255() {
       const int m = parser.value_int();
       ui.sleep_timeout_minutes = constrain(m, SLEEP_TIMEOUT_MIN, SLEEP_TIMEOUT_MAX);
     #else
-      const int s = parser.value_int() * 60;
+      const unsigned int s = parser.value_ushort() * 60;
       ui.lcd_backlight_timeout = constrain(s, LCD_BKL_TIMEOUT_MIN, LCD_BKL_TIMEOUT_MAX);
     #endif
   }
diff --git a/Marlin/src/inc/Conditionals_adv.h b/Marlin/src/inc/Conditionals_adv.h
index 9931409976b6..0cc1556a837e 100644
--- a/Marlin/src/inc/Conditionals_adv.h
+++ b/Marlin/src/inc/Conditionals_adv.h
@@ -591,6 +591,10 @@
   #define HAS_PRINT_PROGRESS 1
 #endif
 
+#if ANY(HAS_MARLINUI_MENU, ULTIPANEL_FEEDMULTIPLY, SOFT_RESET_ON_KILL)
+  #define HAS_ENCODER_ACTION 1
+#endif
+
 #if STATUS_MESSAGE_TIMEOUT_SEC > 0
   #define HAS_STATUS_MESSAGE_TIMEOUT 1
 #endif
diff --git a/Marlin/src/lcd/marlinui.h b/Marlin/src/lcd/marlinui.h
index 1c2c48432322..df72538397a2 100644
--- a/Marlin/src/lcd/marlinui.h
+++ b/Marlin/src/lcd/marlinui.h
@@ -32,10 +32,6 @@
   #include "tft_io/touch_calibration.h"
 #endif
 
-#if ANY(HAS_MARLINUI_MENU, ULTIPANEL_FEEDMULTIPLY, SOFT_RESET_ON_KILL)
-  #define HAS_ENCODER_ACTION 1
-#endif
-
 #if E_MANUAL > 1
   #define MULTI_E_MANUAL 1
 #endif
@@ -273,8 +269,8 @@ class MarlinUI {
   #endif
 
   #if LCD_BACKLIGHT_TIMEOUT
-    #define LCD_BKL_TIMEOUT_MIN 1
-    #define LCD_BKL_TIMEOUT_MAX (60*60*18) // 18 hours max within uint16_t
+    #define LCD_BKL_TIMEOUT_MIN 1u
+    #define LCD_BKL_TIMEOUT_MAX UINT16_MAX // Slightly more than 18 hours
     static uint16_t lcd_backlight_timeout;
     static millis_t backlight_off_ms;
     static void refresh_backlight_timeout();
diff --git a/buildroot/tests/mega2560 b/buildroot/tests/mega2560
index 969b3b14ccbc..aa425564fcad 100755
--- a/buildroot/tests/mega2560
+++ b/buildroot/tests/mega2560
@@ -206,16 +206,17 @@ opt_enable REPRAP_DISCOUNT_SMART_CONTROLLER SDSUPPORT EEPROM_SETTINGS EEPROM_BOO
 exec_test $1 $2 "MEGA2560 RAMPS | Laser Feature | Air Evacuation | Air Assist | Cooler | Laser Safety Timeout | Flowmeter | 44780 LCD " "$3"
 
 #
-# Test redundant temperature sensors + MAX TC
+# Test redundant temperature sensors + MAX TC + Backlight Timeout
 #
 restore_configs
 opt_set MOTHERBOARD BOARD_RAMPS_14_EFB EXTRUDERS 1 \
         TEMP_SENSOR_0 -2 TEMP_SENSOR_REDUNDANT -2 \
         TEMP_SENSOR_REDUNDANT_SOURCE E1 TEMP_SENSOR_REDUNDANT_TARGET E0 \
-        TEMP_0_CS_PIN 11 TEMP_1_CS_PIN 12
-opt_enable MPCTEMP
+        TEMP_0_CS_PIN 11 TEMP_1_CS_PIN 12 \
+        LCD_BACKLIGHT_TIMEOUT 30
+opt_enable MPCTEMP MINIPANEL
 opt_disable PIDTEMP
-exec_test $1 $2 "MEGA2560 RAMPS | Redundant temperature sensor | 2x MAX6675" "$3"
+exec_test $1 $2 "MEGA2560 RAMPS | Redundant temperature sensor | 2x MAX6675 | BL Timeout" "$3"
 
 #
 # Polargraph Config