To make it "new" or virgin they need to replace the CPU an the baseband, I'm not sure how they manage the secure enclave problem as the touch id is tied to the CPU.
Yeah this is wrong. You would need to replace the CPU, both eeproms, and baseband CPU, along with reprogramming the nand with the matching serial and mac address from the clean components. Its not feasible. Now for an ipad, thats another story. I've done hundreds of unlocks for them, since they either don't have an IMEI or can easily be converted to Wifi only, then you only need to remove the nand and reprogram with clean activation data that can easily and cheaply be found online from old retired ipads that are no longer in use. Sometimes you have to replace the wifi modules, as the drivers are different between wifi only and cellular versions.
The article linked to a 34 minute YouTube video which demonstrated one unlock method: they replaced a locked iPhone's CPU, baseband CPU, baseband EPROM, NAND Flash (reprogrammed), and touch ID sensor with ones from a donor iPhone and were able to restore iOS.
