We’ve scanned XDA-Developers, 4PDA (Russian forum), and dedicated car-radio blogs. Here are the (as of this writing):
Click and then connect the power/battery to the head unit to trigger the flash. 4. Critical Pre-Update Warnings 8227l Android 12 Firmware Download HOT-
Extract the firmware zip and copy the two main files to the root of the drive (no folders). Initiate Update: Plug the drive into the head unit. We’ve scanned XDA-Developers
Flash Magisk v26+ patched boot image (available on 4PDA). 4PDA (Russian forum)