This is the holy grail for Android head unit firmware. While you will need to use a browser translator, their community has archived almost every 8227L firmware version in existence.
Remember: backup your old firmware, use a FAT32 USB in the GPS slot, and always verify the checksum of your download. Join the XDA or 4PDA threads to stay updated on future "extra quality" releases. android auto firmware latest update 8227l extra quality
Power off the unit, insert the USB, and power it on. If it isn't detected, repeatedly tap the center of the screen during boot until "detected" appears in green. This is the holy grail for Android head unit firmware
Despite "Extra Quality" claims, some bugs persist in the 8227L ecosystem: Join the XDA or 4PDA threads to stay
Re-flash your MCU file (separate from firmware). Download your original MCU from the forum and use the "MCU Update" option in factory settings.