diff --git a/targets/TARGET_STM/mbed_rtx.h b/targets/TARGET_STM/mbed_rtx.h
index 0227a2c8eb..7fbc864bdb 100644
--- a/targets/TARGET_STM/mbed_rtx.h
+++ b/targets/TARGET_STM/mbed_rtx.h
@@ -130,9 +130,11 @@
 
 #endif // INITIAL_SP
 
+#if (defined(TARGET_STM32F070RB) || defined(TARGET_STM32F072RB))
 #ifdef MBED_CONF_RTOS_MAIN_THREAD_STACK_SIZE
 #undef MBED_CONF_RTOS_MAIN_THREAD_STACK_SIZE
 #endif
 #define MBED_CONF_RTOS_MAIN_THREAD_STACK_SIZE 3072
+#endif
 
 #endif  // MBED_MBED_RTX_H