As we mentioned earlier, iOS 4.0.2 doesn’t update the iPhone Baseband, therefore you can still use Ultrasn0w to unlock your iPhone. This guide with show you how to unlock iOS 4.0.2 using Ultrasn0w.

Note: Currently you can only unlock iPhone 3G on iOS 4.0.2.

Step 1: Sync your iPhone with iTunes to back-up all your important data including settings, apps, music, contacts and photos.

Step 2: Jailbreak your iPhone using Redsn0w v0.9.5b5-5 (Follow our guide here).

Step 3: Launch “Cydia” on your iPhone.

Step 4: Typically, the Ultrasn0w repo is included with Cydia. If not, tap the “Manage” tab located on the bottom tab bar.

Step 5: Tap “Sources”, “Edit”, then “Add”. You’ll be prompted to add URL source. Type “http://repo666.ultrasn0w.com” and tap “Add Source”.

Step 6: Cydia automatically refreshes and updates sources.

Step 7: 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 “1.1-1″. Ultrasn0w is a software unlock for your iPhone, so you can use it with any carrier by simply inserting the SIM card.

Step 8: Restart iPhone and voila! Your iPhone 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 iPhone. Use at your own risk.