After updating in Android 4.1.2 my screen goes black. Screen works again only when the call is finished. I know about the feature when you put the phone on ear it goes black and the second you remove the phone from your ear , the screen turns on again. But now is different. Now it goes black the same second when I press call and there's nothing that brings it back until the call is over! Please help.
Based from OP's comment, you have to calibrate the proximity sensor:
- Go to "Secret Menu" by dialing
- Select "Device Test"
- Select "All Auto Test Menu Full"
- Choose "ALC / Proximity Test"
I had the same problem with my LG Optimus 4X P880: whenever I wanted to make a call, the screen was going to off position; only after finishing the call it turned back on.
I think it is nothing but a software problem in Android version 4.1.2. So I rolled back from 4.1.2 Jelly Bean to 4.0.3 Icecream Sandwich. Now my phone is working properly.