The Limera1n jailbreak tool is now out to jailbreak iPhone 4 on iOS 4.1. But since iOSUnlock iPhone 4 4.1 Firmware 4.1 upgrades your baseband while updating to it, you will loose your unlock. So you should update your iPhone 4 to iOS 4.1 without upgrading baseband and then jailbreak and unlock it. Here are the steps to unlock iPhone 4 iOS 4.1 firmware.

1. Update iPhone 4 to iOS 4.1 without upgrading the baseband. The guide to do that is given here.

2. Now jailbreak your iPhone 4 using Limera1n. The guide to do that is given here.

3. Now open Cydia and choose the ” Manage ” tab.

4. Choose the ” Sources ” option.

5. Tap the ” Edit ” button and then on the ” Add ” button.

6. Then add the source ” http://repo666.ultrasn0w.com “.

Unlock iPhone 3GS 4.1 Firmware

7. After the source is added, search for ” ultrasn0w 1.1-1 ” in Cydia.

8. Install the Ultrasn0w 1.1-1 app to unlock iPhone 4 4.1 firmware.

Unlock iPhone 3GS 4.1 Firmware

9. Restart your iPhone 4.

That’s it! You will have an unlocked iPhone 4 with you now.