Spoofing a serial number on a MacBook Pro I have a MacBook Pro that got liquid spilled on it. I cleaned it up and everything works except the fact that it no longer has a serial number. When I go to look at System Information, it says "Serial Number: Unavailable." I've tried re-flashing the serial using Apple's Blank Board Serializer tool, which didn't work. I think that the place where the serial is physically stored on the board is somehow broken.

So is there any way to "spoof" a serial number so that FaceTime and iMessage work correctly? I've been looking at trying to set boot arguments, or change kernel extensions, or something. 

Where in the boot sequence does the OS look for the board's serial number, and how can I change that? It seems to be stored in the NVRAM, but I can't access it.
AFAIK, there is no way to clear a serial intentionally or by accident. The only way to get a blank system serial number is when the logic board is replaced. Replacement MLB only comes with a part serial number but it does not have a system serial number. I assume that you took your laptop to have it repaired?

When a new logic board is replaced by Apple or an Apple Certified Service Provider, the logic board needs to be serialized after the repair. Normally an ACMT doing the repair will run basic MRI test after the repair which will then be identified as a blank board thus allowing the ACMT to add a serial number to the board prior to running the test.

You can go back to the repair shop and they will most likely correct the sloppy error of forgetting to add the serial number. If that option is not available then you can try going to the closest Apple store but the only way they will help you is if Apple or an Apple store branch did the repair or an ACSP/ACMT did the repair.