Okay, so here's the daunting and confusing task my friend put before me: If at all possible, get a Sonim XP1 cellphone, to work with a Boost Mobile SIM card. We have: 1) A boost mobile phone, quite generic, doesn't do much. 2) A boost mobile SIM card, with service active currently. 3) A Sonim XP1 phone. 4) A Cingular / AT&T SIM card, without any service active. Unfortunately, it's not as easy as just sticking the Boost Mobile SIM in the Sonim XP1 cellphone and turning it on... I tried it... it doesn't work. I think I actually did get it to read a number off the SIM card, so I think it KNOWS that there's a SIM card in there... but for some reason it doesn't work. Now, from my understanding and what I've been able to gather, Boost Mobile works off an OLD sprint network or something like it, which I believe might use a different type of transmitter / encoder than up-to-date services (Say AT&T's service.) use. I don't know if it's at all possible with the hardware to get the SIM working with the SONIM XP1 phone, but if it is, we'd be glad to be rid of this crappy Boost Mobile phone.