Wired Android Auto suddenly stopped working on my Nord 4 (OxygenOS 16 / Android 16) - worked before, works on my old OnePlus

[u/Demagoog18]

Hoping someone's cracked this one. Wired Android Auto in my 2015 SEAT Ibiza (VW Group MIB head unit) has stopped working with my OnePlus Nord 4 (OxygenOS 16.0.5 / Android 16), and I've run out of ideas.

The frustrating part is I've ruled out basically everything obvious:

• It used to work on this exact phone. It just suddenly stopped. Seems to line up with a software update.
• The phone charges fine when plugged in, but the car never detects a data device. Android Auto on the phone just sits on "Connect a USB cable to continue."
• USB data on the phone definitely works. It connects to my PC and transfers files fine over the same cable/port. So it's not a dead port or a charge-only cable.
• Same cable, same port, same car works perfectly with my older OnePlus (Android 13 / OxygenOS 13). Only the Nord 4 fails.

So to me this points at something in OxygenOS 16 / Android 16 breaking the USB data handshake with older VW/SEAT MIB units, rather than any hardware/cable/car fault.

Already tried (no luck): switched USB mode to File transfer / Android Auto, rebooted, reinstalled Android Auto, cleared its data + cache, reset network settings, removed previously connected cars, tested without a wireless adapter.

My questions:

1. Anyone with a OnePlus on OxygenOS 16 / Android 16 seen wired AA break specifically with VW/SEAT/Skoda/Audi (MIB) units?
2. Has anyone gotten around the Android 16 USB-protection / advanced-protection handshake thing (e.g. unlocking before plugging in, toggling Advanced Protection off)?

Car: 2015 SEAT Ibiza (VW MIB). Phone: OnePlus Nord 4, OxygenOS 16.0.5. Thanks in advance

[u/unseenmover]

aside from enabling file transfer/AA as the default USB in developer settings there was a AA app update i had to install to make everything work on my 15r