This is the most common legitimate scenario. A technician buys a "donor" M1 board from a liquid-damaged or physically broken MacBook. They repair a different MacBook by swapping in that donor board. Now, they have a working MacBook (Motherboard B) with the Serial Number of the donor machine (Motherboard A). The screen, trackpad, and top case have the original serial number (Machine C). The result? Mismatched serials causing iCloud lockouts, activation lock issues, and "Unable to verify display" pop-ups.
Before discussing how to change a serial number, we must understand what the serial number does in the M1 ecosystem. macbook m1 change serial number
The cryptographic handshake requires a valid Apple Service Provider account. No third-party tool can emulate this. This is the most common legitimate scenario
: Improperly rewriting firmware can make the MacBook unbootable, requiring DFU mode recovery via another Mac and Apple Configurator Feature Loss Now, they have a working MacBook (Motherboard B)