Today I was asked to upgrade an LG Optimus Black P970 Android phone from 2.2 to 2.3.4 (official release). After that I encountered some problems and here is how to fix them. I suppose this applies to other phones as well.
Upgrading Android was easy, I used official LG update tool. During the process it got stuck at 6-7% and said that it lost communication with device so you have to remove the battery and plug the cable again.... but WAIT - don't remove the battery, just re-plug the cable and it will work.
After it was done, usually during the process your settings and apps should not be wiped. It wasn't in my case. After the update, process com.android.phone started to crash every time I tried to access the SIM card, or when it would register onto the network, or do anything related to GSM networking actually....
I was also surprised that no information whatsoever was available to solve this issue.
So I just tried to reset to factory settings after trying numerous other solutions I found for other phones. Of course reseting the phone wipes the data, but you can backup stuff, I didn't.
After the wipe it was resolved and was working fine.
The phone was a stock Android.
