diff --git a/Marlin/src/HAL/HAL.h b/Marlin/src/HAL/HAL.h
index 1e0de556f0..80a9680698 100644
--- a/Marlin/src/HAL/HAL.h
+++ b/Marlin/src/HAL/HAL.h
@@ -31,22 +31,21 @@
 
 #include "SPI.h"
 
+#define CPU_32_BIT
+
 #ifdef __AVR__
+  #undef CPU_32_BIT
   #include "HAL_AVR/HAL_AVR.h"
 #elif defined(ARDUINO_ARCH_SAM)
-  #define CPU_32_BIT
   #include "HAL_DUE/HAL_Due.h"
   #include "math_32bit.h"
 #elif defined(__MK64FX512__) || defined(__MK66FX1M0__)
-  #define CPU_32_BIT
   #include "HAL_TEENSY35_36/HAL_Teensy.h"
   #include "math_32bit.h"
 #elif defined(TARGET_LPC1768)
-  #define CPU_32_BIT
   #include "math_32bit.h"
   #include "HAL_LPC1768/HAL.h"
 #elif defined(__STM32F1__) || defined(TARGET_STM32F1)
-  #define CPU_32_BIT
   #include "math_32bit.h"
   #include "HAL_STM32F1/HAL_Stm32f1.h"
 #else