My LG d802 phone's touch screen has broken. It has been replaced with all new screen. In the same time, I get 5.0.2 v30b update. Now knock on(double tap screen on) is not working. But screen off working well. I updated touch firmware at the hidden menu , I flashed same Rom 5.0.2 v30b and I formated with hard reset. Still not working. Is that a software problem or hardware problem. Should I make root or flash another roms . maybe new screen doesn't support knock on?