The phone is locked to AT&T, but I tried a t-mobile sim and it took it, shows full bars for a local carrier (Movistar), but won't take any local sims. Under Settings, "more information" it says operator "t-mobile 15.1", Network "Movistar". I even received two text messages, welcoming me to my country, and warning me about data charges. Itunes recognizes the phone, lets me backup, etc. Can anyone explain how this is possible?