diff --git a/ports/stm/common-hal/microcontroller/Pin.c b/ports/stm/common-hal/microcontroller/Pin.c
index e966f709f6..f474414b39 100644
--- a/ports/stm/common-hal/microcontroller/Pin.c
+++ b/ports/stm/common-hal/microcontroller/Pin.c
@@ -55,7 +55,7 @@ bool neopixel_in_use;
 
 
 STATIC uint16_t claimed_pins[GPIO_PORT_COUNT];
-STATIC uint16_t never_reset_pins[GPIO_PORT_COUNT];
+STATIC uint16_t __ALIGNED(4) never_reset_pins[GPIO_PORT_COUNT];
 
 void reset_all_pins(void) {
     // Reset claimed pins