Main Screen Blocked


karmine1994

Members
Feb 21, 2017
36
20
i have a problem since 3 updates.. sometimes, when i do a call to someone, when i touch on contact and the call starts, main screen go black and i cant unlock the phone.. i can unlock only when the call is finished! and a lot of time the mobile asks me to press BACK and UP VOLUME before to unlock... why and how can i fix it?
 
in mi4c 7.7.20 it is under settings / advanced settings/ security /trusted devices