diff --git a/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h b/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
index b9aa85744e..4c67a307ea 100644
--- a/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
+++ b/rtos/rtx/TARGET_CORTEX_M/RTX_CM_lib.h
@@ -351,7 +351,8 @@ __attribute__((used)) void _mutex_release (OS_ID *mutex) {
 /* Main Thread definition */
 extern void pre_main (void);
 
-#if defined(TARGET_MCU_NRF51822) || defined(TARGET_MCU_NRF52832)
+#if defined(TARGET_MCU_NRF51822) || defined(TARGET_MCU_NRF52832) || defined (TARGET_STM32F334R8) ||\
+    defined(TARGET_STM32F302R8) || defined(TARGET_STM32F303K8) || defined (TARGET_STM32F334C8)
 static uint32_t thread_stack_main[DEFAULT_STACK_SIZE / sizeof(uint32_t)];
 #else
 static uint32_t thread_stack_main[DEFAULT_STACK_SIZE * 2 / sizeof(uint32_t)];