diff --git a/firmware/fsm.c b/firmware/fsm.c
index 15359c8..f88e371 100644
--- a/firmware/fsm.c
+++ b/firmware/fsm.c
@@ -106,7 +106,11 @@ void fsm_sendSuccess(const char *text)
 	msg_write(MessageType_MessageType_Success, resp);
 }
 
+#if DEBUG_LINK
+void fsm_sendFailureDebug(FailureType code, const char *text, const char *source)
+#else
 void fsm_sendFailure(FailureType code, const char *text)
+#endif
 {
 	if (protectAbortedByInitialize) {
 		fsm_msgInitialize((Initialize *)0);
@@ -156,10 +160,18 @@ void fsm_sendFailure(FailureType code, const char *text)
 				break;
 		}
 	}
+#if DEBUG_LINK
+	resp->has_message = true;
+	strlcpy(resp->message, source, sizeof(resp->message));
+	if (text) {
+		strlcat(resp->message, text, sizeof(resp->message));
+	}
+#else
 	if (text) {
 		resp->has_message = true;
 		strlcpy(resp->message, text, sizeof(resp->message));
 	}
+#endif
 	msg_write(MessageType_MessageType_Failure, resp);
 }
 
diff --git a/firmware/fsm.h b/firmware/fsm.h
index b91129a..24861a2 100644
--- a/firmware/fsm.h
+++ b/firmware/fsm.h
@@ -25,7 +25,14 @@
 // message functions
 
 void fsm_sendSuccess(const char *text);
+
+#if DEBUG_LINK
+void fsm_sendFailureDebug(FailureType code, const char *text, const char *source);
+
+#define fsm_sendFailure(code, text) fsm_sendFailureDebug((code), (text), __FILE__ ":" VERSTR(__LINE__) ":")
+#else
 void fsm_sendFailure(FailureType code, const char *text);
+#endif
 
 void fsm_msgInitialize(Initialize *msg);
 void fsm_msgGetFeatures(GetFeatures *msg);