diff --git a/firmware/development/wave_analyzer.cpp b/firmware/development/wave_analyzer.cpp
index 04926fe3a6..1db6514db2 100644
--- a/firmware/development/wave_analyzer.cpp
+++ b/firmware/development/wave_analyzer.cpp
@@ -60,6 +60,7 @@ static void waAnaWidthCallback(WaveReader *reader) {
 	efitick_t nowUs = getTimeNowUs();
 	reader->riseEventCounter++;
 	reader->lastActivityTimeUs = nowUs;
+	assertIsrContext(CUSTOM_ERR_6670);
 	addEngineSniffferEvent(reader->name, WC_UP);
 
 	uint32_t width = nowUs - reader->periodEventTimeUs;
@@ -73,6 +74,7 @@ void WaveReader::onFallEvent() {
 	efitick_t nowUs = getTimeNowUs();
 	fallEventCounter++;
 	lastActivityTimeUs = nowUs;
+	assertIsrContext(CUSTOM_ERR_6670);
 	addEngineSniffferEvent(name, WC_DOWN);
 
 	efitick_t width = nowUs - widthEventTimeUs;
diff --git a/firmware/util/rfiutil.h b/firmware/util/rfiutil.h
index 34950d3db0..4060ea8db8 100644
--- a/firmware/util/rfiutil.h
+++ b/firmware/util/rfiutil.h
@@ -22,6 +22,8 @@
 #define isLocked() (ch.dbg.lock_cnt > 0)
 #define isIsrContext() (ch.dbg.isr_cnt > 0)
 
+#define assertIsrContext(code) efiAssertVoid(code, isIsrContext(), "NOT_ISR")
+
 #ifdef __cplusplus
 extern "C"
 {