diff --git a/port/platform/stm32cube/u_cfg_os_platform_specific.h b/port/platform/stm32cube/u_cfg_os_platform_specific.h
index 714207f7..78132e91 100644
--- a/port/platform/stm32cube/u_cfg_os_platform_specific.h
+++ b/port/platform/stm32cube/u_cfg_os_platform_specific.h
@@ -66,7 +66,7 @@
 # ifdef CMSIS_V2
 #  define U_CFG_OS_PRIORITY_MAX 55
 # else
-#  define U_CFG_OS_PRIORITY_MAX 15
+#  define U_CFG_OS_PRIORITY_MAX 14
 # endif
 #endif