I have this problem practically every time I reboot : ) Go into settings in your menu, go into USB Mode Select and uncheck Host Mode box or check it and then uncheck. When you go back to your main screen you should see your USB device being recognized in the top left corner. Not sure if this is normal or a glitch but it solves the problem for me every time! Granted, this is if your USB port/driver isn't broken... Hope it helps!!!