On older Macs, the serial number was often stored on a programmable chip (EEPROM) that could sometimes be modified using specific "Blank Board Serializer" tools. However, the M1 chip changed the game.

“No user-accessible method exists to change the serial number on an Apple Silicon (M1) MacBook. Attempting to do so via non-Apple tools will permanently brick the device. The only legitimate path is Apple or an AASP using internal System Configuration tools after a repair.”

: Users who replace a bottom case or logic board with third-party parts may find their About This Mac

Leo quickly diagnosed the problem: corrupted SSD controller logic, but the bigger issue was that the device was activation-locked to an unknown Apple ID. When Leo asked for proof of purchase, the customer grew nervous, mumbled something about a “gift,” and left the machine behind.