Unbreaking Android Fingerprint Profiles

This is essentially a reproduction of an xda-developers forum post, but it was on the n^th page of Google results.

Symptoms

• inability to enrol/de-enrol fingerprints
• “Fingerprint hardware not available” messages
• Unable to unlock the device with fingerprints

Fix

This fix assumes you’re running TWRP, but anything which allows write access to /data should work.

1. Boot into TWRP
2. Go to Advanced > File Manager
3. Navigate to /data/system/user/0 (assuming the default profile)
4. Remove fpdata/user.db and settings_fingerprint.xml
5. Reboot into Android and observe that fingerprints are gone and enrolment is working!