Hi i recently purchased an iPhone 4s from my friend but it is locked to a carrier different from the one i use. when my sim is in the phone and i turn it on it cannot be used and displays the "Only compatible sim cards can be used..." or whatever message. i looked online how to unlock it and everywhere said i needed to jailbreak it first. so i tried doing so with absinthe, pwngetool and ziphone except they all say they cant detect an iphone or one is not connected, when it is. i tried dfu mode with all of these and same thing. the only thing that seems to have any effect is redsn0w, which allows the phone to be used, gives me cydia, but still says there is no service and i cant make calls etc. (although i can still connect to wireless) also when i try to install packages or themes or whatever from cydia they do not work. ive tried installing ultrasn0w from cydia to unlock it but still it didnt work (no service) does anyone have any ideas what i should do? if anyone has any solutions could they please tell me step by step instructions? ( tl;dr: Need to know how to jailbreak and unlock an iphone with a sim from a carrier different to the one the phone is locked to. thank you very much in advance.