How to Unlock iOS 4.2.1, Ultrasn0w Released

The much awaited iOS 4.2.1 unlock has been released moments ago by the Dev Team. The Ultrasn0w unlock works on the latest iPhone 4 as well as iPhone 3G/3GS though not all basebands are supported on the newer iPhone 4 yet. For everyone waiting for working iPhone 4.2.1 unlocking solution, the wait is now over.


For owners of factory unlocked iPhones like me this is not a big news but for those with career locked iPhones, a working iPhone 4.2.1 unlock would be just priceless.

Ultrasn0w has been updated to version 1.2 and now lets you unlock iOS 4.2.1 with following basebands:

iPhone 3G / 3GS Basebands:

  • 04.26.08
  • 05.11.07
  • 05.12.01
  • 05.13.04
  • 06.15.04 (those stuck on 05.14 or 05.15 should first upgrade to 06.15 to unlock)

iPhone 4

  • 01.59.00

Apprently, iPhone 4’s newer basebands are more difficult to unlock and will take a few days more. So, the Dev Team decided to release the unlock for the rest of the people.

How to Unlock iOS 4.2.1

  • Head to Cydia.
  • Add ultrasn0w repo –¬†
  • Install Ultrasn0w 1.2
  • Reboot iPhone

You should be able to use any SIM card from careers other than the one the iPhone was locked to. In case you have trouble unlocking iPhone or following these instructions don’t worry we will be publishing full tutorials soon to unlock each iPhone.