diff --git a/grbl/system.c b/grbl/system.c
index 491dfdf..413aa7b 100644
--- a/grbl/system.c
+++ b/grbl/system.c
@@ -350,58 +350,52 @@ uint8_t system_check_travel_limits(float *target)
 
 
 // Special handlers for setting and clearing Grbl's real-time execution flags.
+// ARM: interrupts are always enabled, even within ISRs. We don't have
+// to check on entry.
 void system_set_exec_state_flag(uint8_t mask) {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_state |= (mask);
-  if(en) __enable_irq();
+  __enable_irq();
 }
 
 void system_clear_exec_state_flag(uint8_t mask) {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_state &= ~(mask);
-  if(en) __enable_irq();
+  __enable_irq();
 }
 
 void system_set_exec_alarm(uint8_t code) {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_alarm = code;
-  if(en) __enable_irq();
+  __enable_irq();
 }
 
 void system_clear_exec_alarm() {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_alarm = 0;
-  if(en) __enable_irq();
+  __enable_irq();
 }
 
 void system_set_exec_motion_override_flag(uint8_t mask) {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_motion_override |= (mask);
-  if(en) __enable_irq();
+  __enable_irq();
 }
 
 void system_set_exec_accessory_override_flag(uint8_t mask) {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_accessory_override |= (mask);
-  if(en) __enable_irq();
+  __enable_irq();
 }
 
 void system_clear_exec_motion_overrides() {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_motion_override = 0;
-  if(en) __enable_irq();
+  __enable_irq();
 }
 
 void system_clear_exec_accessory_overrides() {
-  uint8_t en = __get_PRIMASK();
   __disable_irq();
   sys_rt_exec_accessory_override = 0;
-  if(en) __enable_irq();
+  __enable_irq();
 }