I don't know how long this would last, but it does work. I'm upgrading my mom with my old iPhone 3GS. Since I couldn't get in touch with AT&T to update the SIM/IMEI number, I swapped SIM cards. She's got a functional phone and can use apps and such as long as she's on WiFi. So it can be done. I do plan to get her fully activated once I can call AT&T during business hours. She was already hooked just by having all 3300 photos available on her phone.