I have a Fascinate that I gave my wife. She had an old flip phone, and I moved her to a smartphone. When I had last used this two years back, I had a rooted rom version DL09. It worked, but I didn't care for the Fascinate so I moved on.
My wife is anti-tech, so I un-rooted it by downloading and installed a stock EH03 tar file. I then set up the phone for her with the basics.
All is well, so I thought.
Whenever she would be on the phone, placing or receiving a call, the phone screen, as expected, goes blank when near the face due to the proximity sensor. But if you put it near your face a second time, it goes blank and locks up. Nothing will recover the blank screen but a battery pull. I reproduced this a dozen times with my hand near the proximity sensor and away. On the second screen blank, it locks up.
I tried a couple of factory resets, but no go. I flashed back to DL09, and everything is well again. No problem on DL09. You can blank the screen a dozen times when on a call with no issues.
I then let the Fascinate automatically update from Verizons network from DL09. I forget what it update to now, but I believe it was something other than EH03. After the Verizon update, boom, back to the lock up issue.
I flashed back to DL09 and I'm leaving it there. Warned her to never accept any updates.

Any ideas?