Help !!
My wife and I wanted to update the Navi unit on my wife´s car with newer maps and purhased a Navi Update (2 dvds, Comand APS 2017/2018, part # A212 827 33 00, version 12) from our local Mercedes Benz dealership here in Norway. When trying to run the update, the process stopped at 32% completion while the #1 update dvd was running. No matter what I do, I can´t get the update process to proceed. So now the navigation no longer works. I have had the dealership look into this and they seem unable to solve the issue. Seems the dealership has attempted to update the firmware in the comand unit and now I have also lost the lingatronics or voice comand capability of the unit as well (but gained BT sreaming capability). The dealership techs also say the unit can not be reset to the original maps either. After several iterations the dealership now says the the dvd reader in the comand unit must be faulty and that I need to have them replace the whole comand unit at a estimated cost of 29,000 norwegian kr (about 2900 euros). I do not believe the dvd reader is causing this since the unit reads/plays DVD movies just fine. Anyone out there who has experience with this or can offer and advice on how to proceed?

Thanks, the NTG 4 navi system only has a dvd changer in the main unit (no additional drive) and I have tried updating having both update dvds in the changer but get the same error message.