Last week, Apple released iOS 4.0.1 for iPhone 3G, 3GS, and iPhone 4. The new firmware did not include a baseband update, but the process of updating your iPhone, via iTunes, locks your iPhone again, to whatever carrier you bought it from. Luckily, if you can jailbreak your iPhone on iOS 4.0.1, you can still unlock with Ultrasn0w. You can jailbreak your iPhone 3G on iOS 4.0.1 with Redsn0w, and you can jailbreak your iPhone 3GS on iOS 4.0.1 with Sn0wBreeze.

Once you’ve jailbroken your device, here’s what you gotta do to unlock:

1. Launch “Cydia” on your iDevice.

2. Typically, the Ultrasn0w repo is included with Cydia. If not, tap the “Manage” tab located on the bottom tab bar.

3. Tap “Sources”, “Edit”, then “Add”. You’ll be prompted to add URL source. Type “http://repo666.ultrasn0w.com” and tap “Add Source”.

4. Cydia automatically refreshes and updates sources.

5. After Cydia is done refreshing sources. Tap the “Search” tab on the bottom tab bar and search for Ultrasn0w. Once Ultrasn0w appears, tap and you should see version “0.93″. Ultrasn0w is a software unlock for your iDevice, so you can use it with any carrier by simply inserting the SIM card.

iPhone DevTeam’s 3G and 3GS software unlock, now with added PwnApple. Compatible with basebands o4.26.08, 05.11.07, 05.12.01 and 05.13.04! Thanks to @sherif_hasim and @ 0ranav for contributing baseband crashes.

6. Restart your iDevice and done! Your iDevice should now be fully unlocked.

Don’t forget to check out our HOW TO section for the latest tips and tricks!

Note: We are not responsible for any damage or loss of data on your iDevice. Use at your own risk.