How to unlock iPhone 3G and 3GS with OS 3.1.3 using ultrasn0w

If you’ve already jailbroken your iPhone using sn0wbreeze and haven’t unlocked it to work with your carrier yet, you can use ultrans0w to unlock it easily. This is possible because sn0wbreeze preserves the older baseband while jailbreaking the iPhone. Here’s a simple guide on how to unlock your iPhone 3G or 3GS with OS 3.1.3 using ultrasn0w:

1. Jailbreak your iPhone using sn0wbreeze v1.3. Follow our guide here.
2. Go to Cydia and tap the manage tab at the bottom.
3. Go to sources, tap Edit and then Add. Add this URL as a source and tap ‘Add Source’: http://repo666.ultrasn0w.com
4. Now go to the search tab and search for ultrasn0w. You’ll find version 0.92. Install it. (T-Mobile users in USA should disable 3G before using ultrasn0w)
5. Restart your iPhone and you’ll have an unlocked phone with firmware 3.1.3!

Thanks to RedmondPie for the guide!