Updated my S4 a few days ago to 4.3 with no problems. All of a sudden today I noticed my battery life was way down and I was unable to open one of my apps. I went in to my my settings and under storage Mount SD card is grayed out. I rebooted multiple times and tried removing and reinserting my card, all with no change. I did notice that sometimes when I reboot now that my boot loader screen is not the stock Samsung screen but says Samsung Custom and shows a picture of an unlocked lock. I have not or never have rooted phone or installed custom firmware. I also tried different SD cards and a factory reset and nothing changed.
