Update::updateBinary():

begin with starting "/opt/app/tools/atbupdate/ATBDownloadDCFirmware".

UpdatePTUDevCtrl/update.cpp

@@ -272,7 +272,14 @@ bool Update::isSerialOpen() const {
                         // bootloader is really not running anymore.
  */
 bool Update::updateBinary(QString const &fileToSendToDC) {
-    qInfo() << "UPDATING DEVICE CONTROLLER FIRMWARE BINARY" << fileToSendToDC;
+
+    QFile dc("/opt/app/tools/atbupdate/ATBDownloadDCFirmware");
+    if (dc.exists()) {
+        qCritical() << "ERROR: dc-binary does not exist" << fileToSendToDC;
+        return false;
+    }
+
+    qInfo() << "updating dc-binary" << fileToSendToDC << "...";
 
     return false;