If i have my sim card in, when I turn on my phone, it says Samsung with a unlocked lock and then word custom beneath it, then the wavy samsung screen, then the at&t screen(which takes longer to load then with no sim). If the sim card isn't inserted, then it boots normal, says Samsung galaxy S4, then the wavy screen, then the at&t screen. And I can't make calls or texts because of sim not provisioned mm #2 error. It was working fine yesterday. Please help. All replies appreciated.