Hello,
you can do it so simply that AUTEL MAXISYS PRO will tell you what you must to do.. So connect with the USB cable your head unit with model and turn the WIFI internet ON. That's ALL. Open coding and chose unit which your want update and etc.. AUTEL will update your unit with last firmware and after that will do a SCN "fresh calibration" via your VIN and fill your unit with ALL necessary data for smooth running.. It work much better and easier than with SD CONNECT 4 and you don't need pay for the access to MB online service..