diff --git a/firmware/controllers/algo/obd_error_codes.h b/firmware/controllers/algo/obd_error_codes.h
index 23dcf229cf..239273637c 100644
--- a/firmware/controllers/algo/obd_error_codes.h
+++ b/firmware/controllers/algo/obd_error_codes.h
@@ -1932,7 +1932,7 @@ typedef enum {
 
 	CUSTOM_ERR_6570 = 6570,
 	CUSTOM_ERR_6571 = 6571,
-	CUSTOM_ERR_6572 = 6572,
+	CUSTOM_ERR_ARRAY_REMOVE = 6572,
 	CUSTOM_ERR_6573 = 6573,
 	CUSTOM_ERR_6574 = 6574,
 	CUSTOM_ERR_6575 = 6575,
@@ -2070,9 +2070,9 @@ typedef enum {
 	CUSTOM_ERR_6695 = 6695,
 	CUSTOM_ERR_6696 = 6696,
 	CUSTOM_ERR_6697 = 6697,
-	CUSTOM_ERR_6698 = 6698,
-	CUSTOM_ERR_6699 = 6699,
-	CUSTOM_ERR_6700 = 6700,
+	CUSTOM_ERR_ARRAY_IS_FULL = 6698,
+	CUSTOM_ERR_ARRAY_REMOVE_ERROR = 6699,
+	CUSTOM_ERR_INVALID_INPUT_ICU_PIN = 6700,
 
 	// this is needed for proper enum size, this matters for malfunction_central
 	Internal_ForceMyEnumIntSize_cranking_obd_code = ENUM_32_BITS,
diff --git a/firmware/controllers/core/fl_stack.h b/firmware/controllers/core/fl_stack.h
index 58b8d37b88..273c0828d1 100644
--- a/firmware/controllers/core/fl_stack.h
+++ b/firmware/controllers/core/fl_stack.h
@@ -107,7 +107,7 @@ ArrayList<Type, Dimention>::ArrayList(void) {
 
 template<class Type, int Dimention>
 void ArrayList<Type, Dimention>::removeAt(int index) {
-	efiAssertVoid(CUSTOM_ERR_6572, index < size, "index greater then size");
+	efiAssertVoid(CUSTOM_ERR_ARRAY_REMOVE, index >= 0 && index < size, "invalid index");
 	memcpy(&elements[index], &elements[size - 1], sizeof(Type));
 	memset(&elements[size - 1], 0, sizeof(Type));
 	size--;
diff --git a/firmware/development/wave_analyzer.cpp b/firmware/development/wave_analyzer.cpp
index ad570f8ac8..31e8c9e563 100644
--- a/firmware/development/wave_analyzer.cpp
+++ b/firmware/development/wave_analyzer.cpp
@@ -127,12 +127,11 @@ static void initWave(const char *name, int index) {
 	reader->name = name;
 
 	reader->hw = addWaveAnalyzerDriver("wave input", brainPin);
+	if (reader->hw != NULL) {
+		reader->hw->widthListeners.registerCallback((VoidInt)(void*) waAnaWidthCallback, (void*) reader);
 
-
-	reader->hw->widthListeners.registerCallback((VoidInt)(void*) waAnaWidthCallback, (void*) reader);
-
-	reader->hw->periodListeners.registerCallback((VoidInt)(void*) waIcuPeriodCallback, (void*) reader);
-
+		reader->hw->periodListeners.registerCallback((VoidInt)(void*) waIcuPeriodCallback, (void*) reader);
+	}
 
 	print("wave%d input on %s\r\n", index, hwPortname(brainPin));
 	startInputDriver(reader->hw, mode);
diff --git a/firmware/hw_layer/digital_input_hw.cpp b/firmware/hw_layer/digital_input_hw.cpp
index 3fc5ccc196..447a87829d 100644
--- a/firmware/hw_layer/digital_input_hw.cpp
+++ b/firmware/hw_layer/digital_input_hw.cpp
@@ -46,6 +46,7 @@ static ICUConfig wave_icucfg = { ICU_INPUT_ACTIVE_LOW, CORE_CLOCK / 100, icuWidt
 
 static ArrayList<digital_input_s, 8> registeredIcus;
 
+//Nullable
 static digital_input_s * finddigital_input_s(ICUDriver *driver) {
 	for (int i = 0; i < registeredIcus.size; i++) {
 		if (registeredIcus.elements[i].driver == driver) {
@@ -145,8 +146,9 @@ icuchannel_t getInputCaptureChannel(brain_pin_e hwPin) {
  *
  * TODO: migrate slow ADC to software timer so that TIM8 is also available for input capture
  * todo: https://github.com/rusefi/rusefi/issues/630 ?
- *
+ * @return NULL if pin could not be used for ICU
  */
+//Nullable
 ICUDriver * getInputCaptureDriver(const char *msg, brain_pin_e hwPin) {
 	if (hwPin == GPIO_UNASSIGNED || hwPin == GPIO_INVALID) {
 		return NULL;
@@ -208,6 +210,10 @@ void turnOnCapturePin(const char *msg, brain_pin_e brainPin) {
  */
 digital_input_s * addWaveAnalyzerDriver(const char *msg, brain_pin_e brainPin) {
 	ICUDriver *driver = getInputCaptureDriver(msg, brainPin);
+	if (driver == NULL) {
+		warning(CUSTOM_ERR_INVALID_INPUT_ICU_PIN, "not input pin");
+		return NULL;
+	}
 
 	digital_input_s *hw = registeredIcus.add();
 	hw->widthListeners.clear();
@@ -247,7 +253,13 @@ void removeWaveAnalyzerDriver(const char *msg, brain_pin_e brainPin) {
 	}
 }
 
-void startInputDriver(digital_input_s *hw, bool isActiveHigh) {
+void startInputDriver(/*nullable*/digital_input_s *hw, bool isActiveHigh) {
+	if (hw == NULL) {
+		// we can get NULL driver if user somehow has invalid pin in his configuration
+		warning(CUSTOM_ERR_INVALID_INPUT_ICU_PIN, "not input pin");
+		return;
+	}
+
 	hw->isActiveHigh = isActiveHigh;
 	if (hw->isActiveHigh) {
 		wave_icucfg.mode = ICU_INPUT_ACTIVE_HIGH;
diff --git a/firmware/hw_layer/digital_input_hw.h b/firmware/hw_layer/digital_input_hw.h
index 808083e964..384d77a71c 100644
--- a/firmware/hw_layer/digital_input_hw.h
+++ b/firmware/hw_layer/digital_input_hw.h
@@ -26,10 +26,12 @@ typedef struct {
 void turnOnCapturePin(const char *msg, brain_pin_e brainPin);
 
 digital_input_s *addWaveAnalyzerDriver(const char *msg, brain_pin_e brainPin);
-void startInputDriver(digital_input_s *hw, bool isActiveHigh);
+void startInputDriver(/*nullable*/digital_input_s *hw, bool isActiveHigh);
 void removeWaveAnalyzerDriver(const char *msg, brain_pin_e brainPin);
 
+//Nullable
 ICUDriver * getInputCaptureDriver(const char *msg, brain_pin_e hwPin);
+//Nullable
 icuchannel_t getInputCaptureChannel(brain_pin_e hwPin);
 
 #endif /* HAL_USE_ICU */