Some tools exist but are:
Official Apple technicians use a proprietary tool to flash a serial number onto a new, blank logic board only once. Once a serial number is set, even official tools cannot easily change it. Scenarios and Solutions macbook m1 change serial number
In the world of Intel-based MacBooks, the act of changing a serial number was a known, albeit niche, practice. Technicians used specialized tools to rewrite the DMI (Desktop Management Interface) data in the SPI flash chip to match a new logic board. However, the arrival of Apple Silicon—specifically the M1 chip—shattered that reality. Some tools exist but are: Official Apple technicians
: Conversely, if the bottom panel was replaced, the number engraved on the metal will no longer match the internal software ID. if the bottom panel was replaced