diff --git a/core/MySensorsCore.cpp b/core/MySensorsCore.cpp
index 9afd2d5..8e5a5fa 100644
--- a/core/MySensorsCore.cpp
+++ b/core/MySensorsCore.cpp
@@ -76,8 +76,10 @@ void _begin() {
 	debug(PSTR("MCO:BGN:INIT " MY_NODE_TYPE ",CP=" MY_CAPABILITIES ",VER=" MYSENSORS_LIBRARY_VERSION "\n"));
 
 	// Call before() in sketch (if it exists)
-	if (before)
+	if (before) {
+		debug(PSTR("MCO:BGN:BFR\n"));	// before callback
 		before();
+	}
 
 	#if defined(MY_LEDS_BLINKING_FEATURE)
 		ledsInit();
@@ -158,6 +160,7 @@ void _begin() {
 
 	// Call sketch setup
 	if (setup) {
+		debug(PSTR("MCO:BGN:STP\n"));	// setup callback
 		setup();
 	}
 
diff --git a/core/MySensorsCore.h b/core/MySensorsCore.h
index e306477..5676840 100644
--- a/core/MySensorsCore.h
+++ b/core/MySensorsCore.h
@@ -40,6 +40,8 @@
  * |E| SYS	| SUB	| Message									| Comment
  * |-|------|-------|-------------------------------------------|----------------------------------------------------------------------------
  * | | MCO  | BGN	| INIT %%s,CP=%%s,LIB=%%s					| Core initialization, capabilities (CP), library version (VER)
+ * | | MCO  | BGN	| BFR										| Callback before()
+ * | | MCO  | BGN	| STP										| Callback setup()
  * | | MCO	| BGN	| INIT OK,ID=%%d,PAR=%%d,DIS=%%d,REG=%%d	| Core initialized, parent ID (PAR), distance to GW (DIS), registration (REG)
  * | | MCO	| BGN	| NODE UNLOCKED								| Node successfully unlocked (see signing chapter)
  * |!| MCO	| BGN	| TSP FAIL									| Transport initialization failed