Clean flashed K20 pro miui 18.104.22.168 stable rom multiple times. Can't add fingerprint. Short reboots (Not full one. Shows miui logo and turns on) occur each time I try to add the fingerprint. After giving the pattern that is required before fingerprint it takes me to add your fingerprint screen. Most of the time it reboots instantly when I try to add the fingerprint. Sometimes it reboots after 1 and 2 touches in the fingerprint scanner (it doesn't give any sign above that fingerprint was recognizing/saving).