Does ADB backup/restore work? Is there a way to boot into recovery? Other than a 12V reset, is there any method to hard reset with no access to System Settings (e.g., soft-bricked)? Is there a technical manual for the head unit's environment, similar as to how there's a technical manual for the automotive side?
Have you looking into Honda Hack? I installed that and it provides options to install additional apps and configure features, like battery voltage, cpu utilization to display on the screen. You can install apps via usb or internet over wifi. Press and hold Audio Power for about 5 seconds and you can reboot the head. We've done that numerous times when Android Auto goes braindead on the head.
HH does not directly, but I think they might have had a wifi ADB tweak. Irrelevant though, as my unit is soft-bricked.
