I updated to 8.1 on my 1520 a few days ago and now the screen will occasionally freeze me out. I can double tap the screen to turn it on but can't swipe the screen up. Also, the screen will also go to a "loading" screen mode sometimes when turning the phone onto the start screen. Sometimes the screen will just stay black too after loading apps or the start screw. Anyone having this issue after losing 8.1 or have any tips?