i just bought an iphone 4 but i have a sim card under t-mobile. it has the newest update from itunes 10.5 which is 5.0.1. the phone currently shows the activation screen with language, region, etc. however, i don't have a sim card which the iphone will recognize to complete the activation, obviously. i've tried jailbreaking it with sn0wbreeze while it's still on the activation screen (with no sim card), but whenever it finishes, all i see is the apple logo with an empty loading bar and i always have to restore to get back to the activation screen. do i need to find a friend's sim card to activate my ios first and then jailbreak? and then am i supposed to have the t-mobile sim card inside while i jailbreak?
my ultimate goal is to get it unlocked so i can use t-mobile. i've read that i need to get cydia through jailbreaking to get it unlocked. if anyone knows any unlock tips, that would be helpful too.