diff --git a/radio/src/CoOS/kernel/OsCore.h b/radio/src/CoOS/kernel/OsCore.h
index 98395db7d..1d18d68f8 100644
--- a/radio/src/CoOS/kernel/OsCore.h
+++ b/radio/src/CoOS/kernel/OsCore.h
@@ -43,7 +43,7 @@
 #include <CoOS.h>
 
 
-#define  OsSchedLock()  OSSchedLock++;      /*!< Lock schedule                */
+#define  OsSchedLock()  { OSSchedLock++; asm volatile ("" : : : "memory"); }      /*!< Lock schedule                */
 extern   void OsSchedUnlock(void);
 
 #endif