diff --git a/lib/cm3/sync.c b/lib/cm3/sync.c
index 3ab9b7e8..c4fbe6d8 100644
--- a/lib/cm3/sync.c
+++ b/lib/cm3/sync.c
@@ -27,7 +27,7 @@ void __dmb()
 
 /* Those are defined only on CM3 or CM4 */
 #if defined(__ARM_ARCH_6M__)
-#warning "sync not supported on ARMv6-M arch"
+/* no work around for cm0 */
 #else
 
 uint32_t __ldrex(volatile uint32_t *addr)