diff --git a/rtos/source/TARGET_CORTEX/rtx5/RTX/Source/rtx_lib.c b/rtos/source/TARGET_CORTEX/rtx5/RTX/Source/rtx_lib.c
index 4f1a456..935b286 100644
--- a/rtos/source/TARGET_CORTEX/rtx5/RTX/Source/rtx_lib.c
+++ b/rtos/source/TARGET_CORTEX/rtx5/RTX/Source/rtx_lib.c
@@ -728,11 +728,12 @@
 //lint -e818 "Pointer 'm' could be declared as pointing to const"
 
 // Initialize mutex
+#if !defined(__ARMCC_VERSION) || __ARMCC_VERSION < 6010050
 __USED
+#endif
 int _mutex_initialize(mutex *m);
-int _mutex_initialize(mutex *m) {
+__WEAK int _mutex_initialize(mutex *m) {
   int result;
-
   *m = osMutexNew(NULL);
   if (*m != NULL) {
     result = 1;
@@ -744,8 +745,10 @@
 }
 
 // Acquire mutex
+#if !defined(__ARMCC_VERSION) || __ARMCC_VERSION < 6010050
 __USED
-void _mutex_acquire(mutex *m);
+#endif
+__WEAK void _mutex_acquire(mutex *m);
 void _mutex_acquire(mutex *m) {
   if (os_kernel_is_active() != 0U) {
     (void)osMutexAcquire(*m, osWaitForever);
@@ -753,8 +756,10 @@
 }
 
 // Release mutex
+#if !defined(__ARMCC_VERSION) || __ARMCC_VERSION < 6010050
 __USED
-void _mutex_release(mutex *m);
+#endif
+__WEAK void _mutex_release(mutex *m);
 void _mutex_release(mutex *m) {
   if (os_kernel_is_active() != 0U) {
     (void)osMutexRelease(*m);
@@ -762,8 +767,10 @@
 }
 
 // Free mutex
+#if !defined(__ARMCC_VERSION) || __ARMCC_VERSION < 6010050
 __USED
-void _mutex_free(mutex *m);
+#endif
+__WEAK void _mutex_free(mutex *m);
 void _mutex_free(mutex *m) {
   (void)osMutexDelete(*m);
 }