[rickdeckard]

Surprise bill for at best "the checksum didn't match so we gave ourselves another paid workorder to investigate the filesystem of your headunit"?

It's more likely that you get it back with a new software (and all your modifications wiped), because as part of the routine maintenance some blue-collar technician connects a USB-dongle and blindly upgrades the firmware.

Unless of course, the modification is so popular that searching for it becomes part of the vendors routine maintenance protocol...