diff --git a/radio/src/pulses/pulses.cpp b/radio/src/pulses/pulses.cpp
index e5ce7c90f..4cd50f240 100755
--- a/radio/src/pulses/pulses.cpp
+++ b/radio/src/pulses/pulses.cpp
@@ -689,7 +689,7 @@ void extmoduleSendNextFrame()
       extmoduleSendNextFrameSoftSerial100kbit(
           extmodulePulsesData.dsm2.pulses,
           extmodulePulsesData.dsm2.ptr - extmodulePulsesData.dsm2.pulses,
-          !GET_SBUS_POLARITY(EXTERNAL_MODULE));
+          GET_SBUS_POLARITY(EXTERNAL_MODULE));
       break;
 
     case PROTOCOL_CHANNELS_DSM2_LP45:
diff --git a/radio/src/pulses/pxx.h b/radio/src/pulses/pxx.h
index c29c29160..f026c7b1c 100644
--- a/radio/src/pulses/pxx.h
+++ b/radio/src/pulses/pxx.h
@@ -107,19 +107,16 @@ class SerialPxxBitTransport: public DataBuffer<uint8_t, 64> {
 
 class PwmPxxBitTransport: public PulsesBuffer<pulse_duration_t, 200> {
   protected:
-    uint16_t rest;
 
     void initFrame(uint32_t period)
     {
       initBuffer();
-      rest = period * 2000; // 0.5uS (2Mhz)
     }
 
     void addPart(uint8_t value)
     {
       pulse_duration_t duration = value ? 47 : 31;
       *ptr++ = duration;
-      rest -= duration + 1;
     }
 
     void addTail()
diff --git a/radio/src/targets/common/arm/stm32/extmodule_driver.cpp b/radio/src/targets/common/arm/stm32/extmodule_driver.cpp
index d73bbcd14..8deddf726 100644
--- a/radio/src/targets/common/arm/stm32/extmodule_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/extmodule_driver.cpp
@@ -65,6 +65,7 @@ void extmodulePpmStart(uint16_t ppm_delay, bool polarity)
 
   ocInit.OCMode = LL_TIM_OCMODE_PWM1;
   ocInit.OCState = LL_TIM_OCSTATE_ENABLE;
+  ocInit.OCNState = LL_TIM_OCSTATE_ENABLE;
 
   if (polarity) {
     ocInit.OCPolarity = LL_TIM_OCPOLARITY_LOW;
@@ -105,7 +106,7 @@ void extmoduleSerialStart()
 
   ocInit.OCMode = LL_TIM_OCMODE_TOGGLE;
   ocInit.OCState = LL_TIM_OCSTATE_ENABLE;
-  ocInit.OCPolarity = LL_TIM_OCPOLARITY_LOW;
+  ocInit.OCPolarity = LL_TIM_OCPOLARITY_HIGH;
   ocInit.CompareValue = 0;
 
   stm32_pulse_config_output(&extmoduleTimer, &ocInit);
@@ -168,9 +169,9 @@ void extmoduleSendNextFrameSoftSerial100kbit(const void* pulses, uint16_t length
 
   uint32_t ll_polarity;
   if (polarity) {
-    ll_polarity = LL_TIM_OCPOLARITY_LOW;
-  } else {
     ll_polarity = LL_TIM_OCPOLARITY_HIGH;
+  } else {
+    ll_polarity = LL_TIM_OCPOLARITY_LOW;
   }
   LL_TIM_OC_SetPolarity(EXTMODULE_TIMER, EXTMODULE_TIMER_Channel, ll_polarity);