The famous unlocking tool: Ultrasn0w can now be used to unlock iOS 4 and the tool supports all type of basebands for iPhone 3GS and also 3G. But unfortunately for new bootrom version of iPhone 3GS there is no chance (at least currently) for you to unlock it, the reason is clear, because before you can unlock your idevice, you need to firstly jailbreak it. And currently no jailbreak available for new bootrom version (check your iPhone 3Gs bootrom version for Windows and check iPhone 3Gs bootrom version for Mac). Therefore it’s better to not upgrading youe OS to iOS 4 if you fully rely on unlock
And now let’s start unlocking the old bootrom version of iPhone 3Gs, iPhone 3G on any baseband including 04.28.08, 05.11.07, 05.12.01 to 05.13.04.
Firstly jailbreak your iPhone 3GS and 3G:
- For iPhone 3GS iailbreak it on iOS 4 with PwnageTool 4.0 or PwnageTool 4.01
- For iPhone 3G jailbreak your device using Redsn0w 0.9.5 B5, read the instructions to jailbreak for Mac and Windows
Now it’s time to unlock your iPhone 3GS and 3G on any baseband running on iOS 4:
- Open Cydia, then tap on Manage tab and then tap on Sources at the buttom
- Now tap on Edit and then on Add. At this phase you will be asked to enter a url address. If that’s so then put this url on it: http://repo666.ultrasn0w.com and then click on Add Source:

- Your url sources will be updated by Cydia now. After it’s finished then search for ultrasn0w 0.93 in Cydia, after you found it then install the app. This application will then doing an automatic unlock to your devices, it means your iPhone 3G or 3Gs will be unlocked to use with any carrier!
- To simply finish the process, just restart your iPhone. Enjoy your unlocking iPhone 3GS or 3G on iOS 4 now!