diff --git a/daemon.go b/daemon.go
index 5ca86a4..d502299 100644
--- a/daemon.go
+++ b/daemon.go
@@ -252,7 +252,7 @@ func (daemon *Daemon) StartHandler(w http.ResponseWriter, _ *http.Request) {
 	}
 
 	errS := fmt.Sprintf("Ignore buttonpress in '%v' status", daemon.job.Status)
-	log.Infof(errS)
+	log.Info(errS)
 	http.Error(w, errS, http.StatusBadRequest)
 }
 
@@ -264,7 +264,7 @@ func (daemon *Daemon) RescheduleHandler(w http.ResponseWriter, _ *http.Request)
 
 	if daemon.job.Status != juggler.StatusWaitingButton {
 		errS := fmt.Sprintf("Ignore reschedule in '%v' status", daemon.job.Status)
-		log.Infof(errS)
+		log.Info(errS)
 		http.Error(w, errS, http.StatusBadRequest)
 		return
 	}
@@ -281,7 +281,7 @@ func (daemon *Daemon) CancelHandler(w http.ResponseWriter, _ *http.Request) {
 
 	if daemon.job.ID == 0 {
 		errS := "Ignore cancel, no job scheduled"
-		log.Infof(errS)
+		log.Info(errS)
 		http.Error(w, errS, http.StatusBadRequest)
 		return
 	}
@@ -302,7 +302,7 @@ func (daemon *Daemon) PauseHandler(w http.ResponseWriter, _ *http.Request) {
 
 	if daemon.job.Status != juggler.StatusPrinting {
 		errS := "Ignore pause, not printing"
-		log.Infof(errS)
+		log.Info(errS)
 		http.Error(w, errS, http.StatusBadRequest)
 		return
 	}
diff --git a/fakejuggler/main.go b/fakejuggler/main.go
index 5bd222f..81e20fd 100755
--- a/fakejuggler/main.go
+++ b/fakejuggler/main.go
@@ -101,25 +101,25 @@ func main() {
 	}
 	j := FakeJuggler{Job: &job}
 
-	http.HandleFunc("/cancel", func(w http.ResponseWriter, r *http.Request) {
+	http.HandleFunc("/cancel", func(w http.ResponseWriter, _ *http.Request) {
 		juggler.SetHeaders(w)
 		log.Println("cancel")
 		j.cancel()
 	})
 
-	http.HandleFunc("/start", func(w http.ResponseWriter, r *http.Request) {
+	http.HandleFunc("/start", func(w http.ResponseWriter, _ *http.Request) {
 		juggler.SetHeaders(w)
 		log.Println("start")
 		j.start()
 	})
 
-	http.HandleFunc("/reschedule", func(w http.ResponseWriter, r *http.Request) {
+	http.HandleFunc("/reschedule", func(w http.ResponseWriter, _ *http.Request) {
 		juggler.SetHeaders(w)
 		log.Println("reschedule")
 		j.reschedule()
 	})
 
-	http.HandleFunc("/info", func(w http.ResponseWriter, r *http.Request) {
+	http.HandleFunc("/info", func(w http.ResponseWriter, _ *http.Request) {
 		juggler.SetHeaders(w)
 		b, err := json.Marshal(j.Job)
 		if err != nil {
@@ -131,13 +131,13 @@ func main() {
 		}
 	})
 
-	http.HandleFunc("/pause", func(w http.ResponseWriter, r *http.Request) {
+	http.HandleFunc("/pause", func(w http.ResponseWriter, _ *http.Request) {
 		juggler.SetHeaders(w)
 		log.Println("pause")
 		j.pause()
 	})
 
-	http.HandleFunc("/version", func(w http.ResponseWriter, r *http.Request) {
+	http.HandleFunc("/version", func(w http.ResponseWriter, _ *http.Request) {
 		juggler.SetHeaders(w)
 		log.Println("version")
 		fmt.Fprintf(w, "12345")
diff --git a/gcodefeeder/feeder.go b/gcodefeeder/feeder.go
index 9adc9a6..1ef261e 100644
--- a/gcodefeeder/feeder.go
+++ b/gcodefeeder/feeder.go
@@ -91,7 +91,8 @@ func (f *Feeder) Cancel() {
 	f.Lock()
 	defer f.Unlock()
 	log.Debug("Feeder: Cancel is called")
-	f.cancelFunc()
+	// Feed, read and write function will terminate when context is cancelled
+	defer f.cancelFunc()
 	instructions := []string{
 		//  turn off temperature
 		"M104 S0\n",
@@ -162,14 +163,11 @@ func (f *Feeder) read(ctx context.Context) {
 					continue
 				}
 				f.status = MMUBusy
-			} else if strings.Contains(bufStr, "start") {
-				// Often "start" comes from MMU, filament sensor etc:
-				// msg="READING:MMU => 'start'"
-				// msg="READING:fsensor_oq_meassure_start"
-				// But the "important" initial start always comes with nothing extra.
-				// Though sometimes it has an old junk (thanks buffered I/O):
-				// msg="READING:\x1bstart"
-				// But still as "Suffix"
+			} else if strings.Contains(bufStr, "start") || strings.Contains(bufStr, "facebook") {
+				// When serial connection is established:
+				// Prusa MK3 returns "start"
+				// Prusa MK4 (Firmware Buddy) returns "facebook"
+				// We consider this event as "ready to print"
 				//
 				// If the first "start" is given - it says printer is ready
 				// If the second "start" is given - somebody reset the printer
@@ -178,6 +176,8 @@ func (f *Feeder) read(ctx context.Context) {
 					seenStart = true
 					f.printerAck <- true
 				} else if seenStart && strings.HasSuffix(bufStr, "start") {
+					// This is most likely a reset button press
+					// TODO: figure out what happens with mk4
 					log.Warning("Feeder: Second 'start' sequence")
 					return
 				}
@@ -229,6 +229,8 @@ func (f *Feeder) Feed() error {
 
 	// Flush whatever junk is in write buffer
 	_, _ = f.writer.Write([]byte("\n"))
+	// Issue a "firmware buddy" specific command to differentiate between mk3 and mk4
+	_, _ = f.writer.Write([]byte("M118 facebook\n"))
 	_ = f.writer.Flush()
 	// Be sure we receive initial reset from printer
 	<-f.printerAck