diff --git a/Marlin/src/HAL/HAL_STM32F7/HAL_STM32F7.h b/Marlin/src/HAL/HAL_STM32F7/HAL_STM32F7.h
index f2196a674..03ab69a1e 100644
--- a/Marlin/src/HAL/HAL_STM32F7/HAL_STM32F7.h
+++ b/Marlin/src/HAL/HAL_STM32F7/HAL_STM32F7.h
@@ -98,7 +98,7 @@
   #define NUM_SERIAL 1
 #endif
 
-#define _BV(bit) (1 << (bit))
+#define _BV(b) (1UL << (b))
 
 /**
  * TODO: review this to return 1 for pins that are not analog input
diff --git a/Marlin/src/HAL/HAL_STM32F7/fastio_STM32F7.h b/Marlin/src/HAL/HAL_STM32F7/fastio_STM32F7.h
index ed74161e0..e22acc667 100644
--- a/Marlin/src/HAL/HAL_STM32F7/fastio_STM32F7.h
+++ b/Marlin/src/HAL/HAL_STM32F7/fastio_STM32F7.h
@@ -29,7 +29,7 @@
 #ifndef _FASTIO_STM32F7_H
 #define _FASTIO_STM32F7_H
 
-#define _BV(bit) (1 << (bit))
+#define _BV(b) (1UL << (b))
 
 #define READ(IO)              digitalRead(IO)
 #define WRITE(IO, v)          digitalWrite(IO,v)
diff --git a/Marlin/src/core/macros.h b/Marlin/src/core/macros.h
index 2c6246723..945233a45 100644
--- a/Marlin/src/core/macros.h
+++ b/Marlin/src/core/macros.h
@@ -95,9 +95,8 @@
 #define STRINGIFY(M) STRINGIFY_(M)
 
 // Macros for bit masks
-#ifndef _BV
-  #define _BV(n)  (1<<(n))
-#endif
+#undef _BV // Marlin needs 32-bit unsigned!
+#define _BV(b) (1UL << (b))
 #define TEST(n,b) (((n)&_BV(b))!=0)
 #define SBI(n,b) (n |= _BV(b))
 #define CBI(n,b) (n &= ~_BV(b))