Hey everyone. Sorry if already posted but I've been reading different threads all day but couldn't find anyone with similar problem and a solution for it. I have an iPhone 3G 4.2.1 and firstly it was updated by mistake via iTunes with official fw, so the baseband was 05.15.04, so I installed 06.15.00 and then downgraded it to 05.13.04, installed ultrasn0w, rebooted several times but it still shows "no service". I also tried reinstalling ultrasn0w and mobilesubstrate with no effect. Installed them via iFunbox - same thing. Sometimes it shows "searching..." after reboot or taking the sim out and back in but after a while it shows "no service" again. Really hope someone can help me unlock this thing.