diff --git a/port/platform/nrf5sdk/u_cfg_os_platform_specific.h b/port/platform/nrf5sdk/u_cfg_os_platform_specific.h
index 8d3e30fd..da523331 100644
--- a/port/platform/nrf5sdk/u_cfg_os_platform_specific.h
+++ b/port/platform/nrf5sdk/u_cfg_os_platform_specific.h
@@ -61,11 +61,10 @@
 #endif
 
 #ifndef U_CFG_OS_PRIORITY_MAX
-/** The maximum task priority, should be less than or
- * equal to configMAX_PRIORITIES defined in FreeRTOSConfig.h,
- * which is set to 15.
+/** The maximum task priority, should be less than configMAX_PRIORITIES
+ * defined in FreeRTOSConfig.h, which is set to 15.
  */
-# define U_CFG_OS_PRIORITY_MAX 15
+# define U_CFG_OS_PRIORITY_MAX 14
 #endif
 
 #ifndef U_CFG_OS_YIELD_MS
diff --git a/port/platform/stm32cube/u_cfg_os_platform_specific.h b/port/platform/stm32cube/u_cfg_os_platform_specific.h
index 0bce8fc9..714207f7 100644
--- a/port/platform/stm32cube/u_cfg_os_platform_specific.h
+++ b/port/platform/stm32cube/u_cfg_os_platform_specific.h
@@ -60,11 +60,11 @@
 #endif
 
 #ifndef U_CFG_OS_PRIORITY_MAX
-/** The maximum task priority, should be less than or
- * equal to configMAX_PRIORITIES defined in FreeRTOSConfig.h.
+/** The maximum task priority, should be less than configMAX_PRIORITIES
+* defined in FreeRTOSConfig.h.
  */
 # ifdef CMSIS_V2
-#  define U_CFG_OS_PRIORITY_MAX 56
+#  define U_CFG_OS_PRIORITY_MAX 55
 # else
 #  define U_CFG_OS_PRIORITY_MAX 15
 # endif