iPhone DEV Team has released the carrier unlocking tool for US iPhone Users who are stuck with AT&T network called UltraSn0w. Apple is selling Unlocked iPhone 4s Internationally but the US users are still locked on the AT&T Network, So those of you who want to use other networks instead of AT&T can install the new UltraSn0w 1.0 to unlock their iPhone's.

Just follow the instructions posted below to unlock your iPhone 4 on iOS 4.0.1 / 4.0 on 01.59.00 baseband.

NOTE: T-Mobile US users will have to disable 3G by navigation to: Settings->General->Network and turning the "Enable 3G" switch to OFF before installing the ultrasn0w unlock.

How to: Jailbreak iPhone 4 on iOS 4.0.1:

Step 1: Unlocking requires that your phone is jailbroken on the latest firmware. Follow the complete guide posted here to jailbreak your iPhone 4 on iOS 4.0.1 / 4.0 using JailbreakMe 2.0.

How to: Unlock iPhone 4 (Any Baseband) on iOS 4.0.1:

Step 2: Once you are done with the jailbreak, you can now unlock your iPhone on any baseband using Ultrasn0w 1.0-1 from Cydia. To do this:

Start “Cydia” on your iPhone.Touch on “Manage” tab on the bottom.Now touch on “Sources” as seen in the screenshot below:

Touch on “Edit” and then on “Add”. You will be prompted to enter a url source as seen in the screenshot below. Type “http://repo666.ultrasn0w.com” and touch on“Add Source” to add this repo if you haven’t already.

Cydia will now automatically update your sources by following a series of automated steps.

After installation is completed. Search for “ultrasn0w 1.0-1” in Cydia and install this application. This app will automatically unlock your iPhone so that you can use it with any carrier.

Step 3: Now simply restart your iPhone and voila! you should now have a fully unlocked iPhone 4 !

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