When I am really busy I sometimes put my phone (Mi2s) into flightmode. But this time I am unable to unlock my sim after turning off flightmode. The keypad is there and I can touch the numbers, but they do not appear on the screen. I tried all the keys, but they do not show up as a code. Just nothing happens when touching te numbers. Few days ago I updated my Mi2s to V6 MIUI. 4.10.24 running now. Last days unlocking my SIM after flightmode was not a problem at all. Restarting the phone does not help. What can I do?!