This guide explains how to update your iPhone 4 to iOS 4.3.1 safely without upgrading baseband. You will also read why it is important to preserve iPhone 4 baseband if you want to unlock your iPhone 4. Ultrasn0w is yet to be updated to support unlocking on iOS 4.3.1 but the untethered jailbreak has already been released.
This tutorial will show you show how to update iPhone 4 to iOS 4.2.1 without upgrading your baseband. This method will preserve iPhone 4’s baseband at 1.59.00 so you don’t lose your software unlock using Ultrasn0w in case you don’t have a factory unlocked iPhone.
The Jailbreak for iPhone 4 and all other iPhones running iOS 4 has already been released online at Jailbreakme.com by Comex in a way few had expected. Now following that here’s the unlock solution for you all. Use your iPhone 3G/ 3GS/ 4 with any carrier worldwide with this unlock.
This guide has actually been tested on the said devices and works like a charm. The unlock via Ultrasn0w will work on your iPhone 3G, iPhone 3GS and iPhone 4 with almost any baseband. However do make sure that your baseband is one of the following:
Go to Settings > General > About > Modem Firmware to get this info.
iPhone 3G / 3GS Basebands:
iPhone 4 Baseband:
If your baseband is present in the lists above, that’s positive sign. Proceed with the instructions here and you will have an iPhone ready for any network. Jailbreak your iPhone if you haven’t done that already.
Steps to follow:
- Launch Cydia
- Click on Manage tab
- Click on Sources. Click on the Repo that reads “repo666.ultrasn0w.com”. If its not present click on Edit and then Add. Type the URL without quotes.
- Click on Ultrasn0w and then on the Install button.
- Finally, Click on Confirm
Make sure you have a working wifi or data connection before you click on Confirm as Cydia will try to download the app. Once the process is over the Reboot Device button will appear. Click on it and wait for your iDevice to restart. And you’re done. While it restarts you may put in any other sim card other than the carrier the phone was locked to. It worked the first time for me and without any issues. The network search is pretty fast and takes around 15 seconds maximum to register network.
Go ahead and unlock your iPhone. Let us know if you run into any issues. We might be able to lend a helping hand as always.