hey all, i appeared to have screwed up my phone. i have the oldder modle of the iphone (not the 3g) it is unlocked and jailbroken. after installing an update the screen shows that it needs to be plugged into itunes and when i do it says that my sim card is not valid. i can only make emergency calls and cant get into the home screen menu. any help to solve this problem would be appreciated greatly. thanks.