diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index 1ed6f97f985..049a38a6a4b 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -127,6 +127,13 @@ static_assert(COUNT(arm) == LOGICAL_AXES, "AXIS_RELATIVE_MODES must contain " _L
 #undef _ISMAX_1
 #undef _ISSNS_1
 
+/**
+ * RADDS is forbidden for non-DUE boards, for now.
+ */
+#if ENABLED(RADDS_DISPLAY) && !defined(__SAM3X8E__)
+  #error "RADDS_DISPLAY is currently only incompatible with DUE boards."
+#endif
+
 /**
  * Heated Bed requirements
  */
diff --git a/Marlin/src/pins/sam/pins_ALLIGATOR_R2.h b/Marlin/src/pins/sam/pins_ALLIGATOR_R2.h
index 87a1260c409..312745f11d1 100644
--- a/Marlin/src/pins/sam/pins_ALLIGATOR_R2.h
+++ b/Marlin/src/pins/sam/pins_ALLIGATOR_R2.h
@@ -153,7 +153,6 @@
   #define LCD_PINS_EN                         15
   #define LCD_PINS_D4                         19
   #define BEEPER_PIN                          64
-  #undef UI_VOLTAGE_LEVEL
   #define UI_VOLTAGE_LEVEL                     1
 #endif