diff --git a/simulator/simulator/rusEfiFunctionalTest.cpp b/simulator/simulator/rusEfiFunctionalTest.cpp
index c8338b03f7..1d586c9334 100644
--- a/simulator/simulator/rusEfiFunctionalTest.cpp
+++ b/simulator/simulator/rusEfiFunctionalTest.cpp
@@ -37,6 +37,7 @@ int getRemainingStack(thread_t*) {
 
 static void assertString(const char*actual, const char *expected) {
 	if (strcmp(actual, expected) != 0) {
+		printf("assertString FAILED\n");
 		firmwareError(OBD_PCM_Processor_Fault, "chprintf test: got %s while %s", actual, expected);
 	}
 }
@@ -47,6 +48,11 @@ static void runChprintfTest() {
 	msObjectInit(&ts, (uint8_t *) testBuffer, sizeof(testBuffer), 0);
 
 
+	ts.eos = 0; // reset
+//	chprintf((BaseSequentialStream*)&ts, "%.2f - %.2f", NAN, 0/0);
+//	ts.buffer[ts.eos] = 0;
+//	assertString(testBuffer, "0.23/239.9320/0.1234");
+
 // it's a very, very long and mostly forgotten story how this became our %.2f precision format
 	ts.eos = 0; // reset
 	chprintf((BaseSequentialStream*)&ts, "%.2f/%.4f/%.4f", 0.239f, 239.932, 0.1234);