Unlock Your iPhone 4.2.1 with UltraSn0w

Dev Team has updated their UltraSn0w iPhone unlock for iOS 4.2.1. UltraSn0w 1.2 will unlock iPhone 4 baseband 01.59.00 and iPhone 3G/3GS basebands 04.26.08, 05.11.07, 05.12.01, 05.13.04 and now 06.15.00.
You can not be able to unlock, if your iPhone is not on the baseband. If your iPhone is on the baseband version like 3G or 3GS,then you can unlock your iPhone and follow the instructions below…
By mistake if your iPhone is not on the baseband version 3G or 3GS, then first you will have to update your baseband to 06.15.00.
In this procedure doesn’t come without its share of risks, so it is very necessary to read this article carefully before doing any thing.So carefully to read this.
Step 1: First check that your iPhone is jailbroken using PwnageTool or RedSn0w.
Step 2: Find the Cydia, and search theUltraSn0w.
Step 3: Download and install UltraSn0w.
Step 4: Shutdown your iPhone.
Now the successfully,your iPhone is unlocked.There is not any other way to unlocked it.