The Dev-Team has released the much anticipated update to the unltrasn0w unlock that unlocks iOS 4.2.1 on the iPhone 3G and 3GS. Below is what they have to say… make sure you read it thoroughly.
Today we’re pleased to announce our free carrier unlock for iPhone3G/3GS owners with a baseband later than 05.13.04. The unlock for that baseband exploited the AT+XAPP command, thanks to a crash initially discovered by @sherif_hashim (@Oranav also found this crash). So what hole are we exploiting today, since Apple closed that AT+XAPP hole? Well, we’re exploiting the exact same hole!