I assume the intent is to swap the Audi Connect SIM with a pay as you go SIM? I am hoping to do the same on my 2017 as I won't pay Audi extortion for Google Maps data via Audi Connect, it is a complete rip off.
The second SIM is in the front of the head unit in the glovebox but from everything I have read that only gives you Internet access via WIFI and Google Maps won't use that connection.
I wish I had done more research before purchasing the technology package as the ongoing costs are WAY out of line. They should allow tethering but failing that, the secondary SIMs should be allowed to supply Google Maps data to the NAV, then you could get a cheap pay as you go or secondary SIM on your AT&T account (I am in CA, USA). I assume the internal SIM would still be in the microSIM form factor. Has anyone opened up the head unit to find out?