https://en.wikipedia.org/wiki/EFuse https://en.wikipedia.org/wiki/EFuse Just needs a jig that connects to a wafer's worth of chips simultaneously with spring l

https://en.wikipedia.org/wiki/EFuse https://en.wikipedia.org/wiki/EFuse Just needs a jig that connects to a wafer's worth of chips simultaneously with spring loaded contact fingers (not on the EFuses themselves, just power, ground, and any way to load code into the µC - i.e. you have bonding pads for this stuff anyway), and have the code burn through an unique combination of fuses.