The firmware can only be loaded via the micro so slot..there are micro ss slot cable extenders if that helps.
Actually once you’ve learnt slowly and painfully how to pull the trim apart it’s not so bad next time around.
The snap in phone unit is a full usb / serial connection.
I’ve wasted a lot of time converting it to a usb port but there’s no apparent logic in the combox to allow it to function as a standard usb port..sadly..
I also made my own custom bmw boot logo for mr 12 volt box splash screen as well as my own logo for the system access within the menu system
https://z4-forum.com/forum/viewtopic...volt&start=525