Updated my Samsung Galaxy S5 1 week ago. Since the update it will not stay connected to wi-fi. Turns on and off every 30 seconds or so and is draining my battery. Turned off the smart switch and did not fix. Had to turn my wi-fi off all together. Can I go back to factory reset? Will that clear the update so I can use my wi-fi again? I have limited data and that doesn't work for me.