diff --git a/cpu/cortexm_common/include/cpu_conf_common.h b/cpu/cortexm_common/include/cpu_conf_common.h
index 33c41d8d8860..db11f78b2ade 100644
--- a/cpu/cortexm_common/include/cpu_conf_common.h
+++ b/cpu/cortexm_common/include/cpu_conf_common.h
@@ -107,7 +107,7 @@ extern "C" {
  * If you want to set this, define it in your `cpu_conf.h`.
  */
 #ifndef CPU_CORTEXM_PRIORITY_GROUPING
-#define CPU_CORTEXM_PRIORITY_GROUPING   (1)
+#define CPU_CORTEXM_PRIORITY_GROUPING   (0)
 #endif
 
 /**
@@ -141,7 +141,7 @@ extern "C" {
  * If you want to set this, define it in your `cpu_conf.h`.
  */
 #ifndef CPU_CORTEXM_PENDSV_IRQ_PRIO
-#define CPU_CORTEXM_PENDSV_IRQ_PRIO (CPU_DEFAULT_IRQ_PRIO + 1)
+#define CPU_CORTEXM_PENDSV_IRQ_PRIO (UINT8_MAX)
 #endif
 /** @} */