I have a malfunctioning proximity sensor which is causing black screen when I make a call. At first, the only way the screen came back is if the other party ends call or I removed the battery. Now I'm able to to get the screen back on if I squeeze the phone close to the center of the screen. Sometimes it will work for a bit and sometimes it doesn't. I tried cleaning the sensor area but no luck. I have not found any app that will kkeep the screen on, is there a solution for this? Could this be software related?