Hello! I'm from Russia and i have a problem with my device. My phone was bought in 2015 year and i used my device with all sim cards without any problems. Yesterday i was made an update ios version from 7.1.2 to last ios version at this moment. So, after that i can't activate my phone! Cuz i see a message in screen " Sim not Support etc". I m sure to remember, before in USA was sprint carrier. What should i do now? Can u help me, please?!