Many people got confused when I published the posts for iPhone 4 and iPhone 3G/3GS unlock with ultrasnow because I didn’t mention the iOS version in the title. So to make the things clear, here I am going to post again the step by step method to unlock iOS 4.0 and iOS 4.0.1 for iPhone 4, iPhone 3GS and iPhone 3G. This unlock works on iPhone4 baseband 01.59 and iPhone 3G/3GS basebands 04.26.08, 05.11.07, 05.12.01 and 05.13.04.
Step by Step HowTo Guide to Unlock iPhone 3GS and iPhone 3G:
Step 2: After jailbreak, run Cydia, search for “ultrasn0w”, download and install it. If you don’t find, add the source. Open Cydia, tap the manage button on the bottom, tap on Sources, click on Edit button of top and then tap Add.
Step 3: Now type this repo address in the sources: http://repo666.ultrasn0w.com (It is zero in ultrasn0w and not O).
Step 4: Tap on Add Source and wait for it to update.
Step 5: Now search for ultrasn0w via search field, tap it and press Install at the top right.
Step 6: Reboot your iPhone4, 3G/3GS and use any carrier on iOS 4.0.1/4.0.
Disclaimer: This guide is for testing & educational purposes only. I’m not responsible for any loss of important data or malfunctioning of your iPhone.