diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
index 5a24edd59f..828ceed09c 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
@@ -186,10 +186,10 @@ void stm32_flash_protect_flash(bool bootloader, bool protect);
 void stm32_flash_unprotect_flash(void);
 
 // allow stack view code to show free ISR stack
-extern uint32_t __main_stack_base__;
-extern uint32_t __main_stack_end__;
-extern uint32_t __main_thread_stack_base__;
-extern uint32_t __main_thread_stack_end__;
+extern stkalign_t __main_stack_base__;
+extern stkalign_t __main_stack_end__;
+extern stkalign_t __main_thread_stack_base__;
+extern stkalign_t __main_thread_stack_end__;
 
 #ifdef __cplusplus
 }