Een hard reset en je bent dan wel je data kwijt...
Gevonden met google:
What happens if it does not recognize my fingerprint when logging on to the device?
In the event that your fingerprint isn't recognized, you should attempt to swipe another enrolled finger, or choose to enter a PIN or Password if you elected these choices when setting up your security settings. If you are unable to authenticate yourself, you will be prompted to hard reset the device after a specified number of unsuccessful attempts.
http://www.fingertech.co....ipaq_5400_series_q&a.html