or an Authorized Service Provider, they use a proprietary "System Configuration" utility to "flash" the original serial number onto the new blank logic board. Missing Serial Number
Can You Change a MacBook M1 Serial Number? Everything You Need to Know
The short answer is: , it's not possible to change the serial number on a MacBook M1 in the classical sense. The serial number is hardcoded into the device's firmware and is not user-modifiable.
Some highly specialized independent micro-soldering technicians possess specialized hardware programmers (such as JCID or JC programmers) capable of reading and writing data to specific sys-config chips on the logic board.