AxoNeuron
macrumors 65816
Even if all of this is true, Apple could easily have included a hardware check DURING the actual update preparation process itself. It would pop up an error saying 'could not update to the latest version of ios'. That works for everybody, both the security types afraid someone will insert a phony malicious touch ID sensor (I find the idea laughable) and the people who had it repaired outside of where an ARS was available. They wouldn't have been able to get the latest ios, but hey, at least they would still have a functional phone...For Apple it is a lot more complicated that this. There is nothing saying that this cares if you have TouchID enabled or not, I suspect it doesn't care either way... The core of the issue is a major component of the security system of the device has been compromised. Since all of the security on your iOS device is done locally with all of the keys being stored on the device in the secure element it locks up when something is outside of expected parameters...
The system is a lot like Secure Boot on Windows 10. Everything has to check out or everything fails. You can't trust anything when one part is out of line so you trust none. Otherwise, the whole system can be compromised.
And once someone had updated to the latest ios, their phone would now be 'protected' against malicious third party touch ID hardware. But at least it wouldn't have hurt anyone who had it repaired 6 months ago long before anyone had even thought this was an issue.