If have read our story on ultrasn0w iOS 4.2.1 unlock release then you would be knowing the process of unlocking iOS 4.2.1 & 4.1 isn’t simple because of patched baseband. The recently released Ultrasn0w 1.2 can unlock iOS 4.2.1 firmware having 05.15.04 baseband or iOS 4.1 with Baseband 05.14.04 provided that you update your baseband to 06.15.00 using PwnageTool 4.1.3 or Redsn0w.

Follow our simple steps if you want to unlock iOS 4.2.1 on iPhone 3G or iPhone 3GS. Ultrasn0w 1.2 can unlock iPhone 4, iPhone 3GS & iPhone 3G if it has following baseband,

Supported Basebands

01.59.00 (iPhone 4 iOS 4.0.2)

04.26.08 (iOS 3.1.1)

05.11.07 (iOS 3.1.2)

05.12.01 (iOS 3.1.3)

05.13.04 (iOS 4.0.2)

06.15.00 (ipad iOS 3.2.2)

If you are stuck on iOS 4.2.1 with Baseband 05.15.04 or iOs 4.1 with baseband 05.14.04 then you need to first update your iPhone baseband to 06.15.00 and then unlock it using Ultrasn0w 1.2. Here is step by step guide on how to Unlock iOS 4.2.1/4.1 on iPhone 3G & iPhone 3GS with Ultrasn0w 1.2.

How to Unlock iOS 4.2.1/4.1 on iPhone 3GS & iPhone 3G

1. You should have jailbroken iPhone 3G/3GS with supported baseband

2. If you are on iOS 4.2.1 or 4.1 then read our how to Update Baseband to 06.15.00 guide.

3. Now launch Cydia app and click on manage tag

4. Now go to source and select edit and add following repo URL

http://repo666.ultrasn0w.com (please note its Zero in world Ultrasn0w and not alphabet ‘o’)

5. Now Let Cydia complete adding & updating packages.

6. Click on Cydia Search and search for “Ultrasn0w” and tap on Ultrasn0w from search result

7. Now click on Install button &  let Ultrasn0w complete unlock process. Now restart your iPhone 3G/3GS and use it your choice of carrier.

That’s iPhone 3G/3GS 4.2.1 unlock accomplished.