diff --git a/radio/src/pulses/pxx.h b/radio/src/pulses/pxx.h
index 90956fe35..a6f78cc54 100644
--- a/radio/src/pulses/pxx.h
+++ b/radio/src/pulses/pxx.h
@@ -30,7 +30,7 @@
 #define PXX2_LOWSPEED_BAUDRATE             230400
 #define PXX2_HIGHSPEED_BAUDRATE            450000
 #define PXX2_NO_HEARTBEAT_PERIOD           4000/*us*/
-#define PXX2_MAX_HEARTBEAT_PERIOD          (7000 + 1000)/*us 7ms frame rate + 1ms heartbeat backup*/
+#define PXX2_MAX_HEARTBEAT_PERIOD          (9000 + 1000)/*us longest period (isrm/accst) + 1ms heartbeat backup*/
 #define PXX2_TOOLS_PERIOD                  1000/*us*/
 #define PXX2_FRAME_MAXLENGTH               64
 
diff --git a/radio/src/targets/common/arm/stm32/heartbeat_driver.cpp b/radio/src/targets/common/arm/stm32/heartbeat_driver.cpp
index 269b40854..ee00a6db3 100644
--- a/radio/src/targets/common/arm/stm32/heartbeat_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/heartbeat_driver.cpp
@@ -79,6 +79,7 @@ void check_intmodule_heartbeat()
 #endif
     EXTI_ClearITPendingBit(INTMODULE_HEARTBEAT_EXTI_LINE);
 
+    mixerSchedulerResetTimer();
     mixerSchedulerISRTrigger();
   }
 }