Yesterday, I shared a guide to jailbreak iPhone OS 4 beta with redsn0w 0.9.5 and now I’m sharing another guide, which will help you unlock your iPhone 3G running on iPhone OS 4 firmware.
However, this unlock will only work with 05.08 bootloader. If you have any other bootloader, ultrasn0w will not work for your device. The steps to unlock the iPhone 3G are pretty much same, but if you are not sure about it, go through the following guide.
Do you want to downgrade your updated iPhone 3G device? iPhone downgrader is here!