[Pomfers]

The fingerprint scanner is just a scanner, it doesn't handle authorization, that's what the security chip does. The scanner has two ways of communicating with the security chip. It can authenticate itself with the chip, and it can send the chip images of fingerprints.

If a compromised scanner fails to authenticate, then the security chip can just ignore the scanner. Not much it can do if its only avenue of communication is cut off. A warning message telling users to not touch their compromised fingerprint scanner would have been sufficient.