I hope there is a solution to this issue. I got an iPhone3Gs which I tried to unlock from its ATnT service to use my other sim card. I went through Googleing it and found a youtube video. Using that video a guide I did all the steps and it seemed to work till I ran Cydia. But unfortunately Cydia did not work so I tried the video steps again but still Cydia did not work. Then later I restored the iOS5.1.1 through iTunes and then after I am unable to activate my iPhone.