diff --git a/demos/STM32/CMSIS-STM32F407-DISCOVERY/main.c b/demos/STM32/CMSIS-STM32F407-DISCOVERY/main.c
index e15a570e6..c71c3103b 100644
--- a/demos/STM32/CMSIS-STM32F407-DISCOVERY/main.c
+++ b/demos/STM32/CMSIS-STM32F407-DISCOVERY/main.c
@@ -33,11 +33,15 @@ static void Thread1(void const *arg) {
   }
 }
 
+/*
+ * Thread definition block.
+ */
+osThreadDef(Thread1, osPriorityAboveNormal, 1, 128);
+
 /*
  * Application entry point.
  */
 int main(void) {
-  osThreadDef(Thread1, osPriorityAboveNormal, 1, 128);
 
   /* HAL initialization, this also initializes the configured device drivers
      and performs the board-specific initializations.*/