iPhone OS 3.0.1 has been released to fix SMS exploit which could remotely control the victim’s iPhone. This guide will help you unlock your iPhone with the latest iPhone OS 3.0.1 firmware using ultrasn0w. This unlocking guide applies to iPhone 3G and iPhone 3GS only. iPhone 2G users can simply follow the guide I posted here to jailbreak and unlock with firmware 3.0.1.

Step 1: Download the latest version of iTunes.

Step 2: Launch iTunes. Make a backup of your phone’s data by right clicking on your iPhone name in the left-hand side sidebar and then click on backup.

Step 3: Now close iTunes and start redsn0w to jailbreak your iPhone (3G and 3GS only) using redsn0w. Please follow the guide here to jailbreak your iPhone 2G, 3G or 3GS using redsn0w.

Step 4: Once you are done with the jailbreak, you can now unlock your iPhone running jailbroken firmware 3.0.1 by using ultrasn0w 0.8. 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”.

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

• After installation is completed. Search for “ultrasn0w” in Cydia and install this application (T-Mobile users should disable 3G before installing ultrasn0w). This app will automatically unlock your iPhone so that you can use it with any carrier.

Step 5: Now simply restart your iPhone. Voila! You are now running a fully unlocked and jailbroken iPhone firmware 3.0.1 on your iPhone 3G and 3GS.

I will also recommend you all to check out the following guides:

Guide to Fix Push Notifications on Hacktivated iPhone 3.0

Fix for Issues when Unlocking and Jailbreaking iPhone 3.0 using redsn0w

How to patch MobileInstallation file on iPhone 3.0

Feel free to ask me any questions here should you run into any problems when unlocking your iPhone.