iPhone 3GS Carrier Lock and how to Unlock it.

Last week a friend of mine called me saying he knew someone who had just moved to Australia from the UK and just wanted to use her iPhone on an Australian carrier.

Normally the original carrier has to remove the carrier restriction from the phone – this person was having immense trouble getting her original carrier to do this though so I sought an alternative way of addressing the problem.

What does a carrier lock do?
A carrier lock prevents a phone from connecting to another mobile network i.e. another carrier. Most carriers today now offer the ability to remove the lock for either a small charge or for free. Unfortunately not all carriers are leniant, or easy to get in contact with.

How to remove it on an iPhone 3GS and iOS variants
To remove the carrier lock we first need to Jailbreak the iPhone so that we can install a package manger called Cydia. To jailbreak you will need to download redsn0w from here. You will also need an iDevice USB cable.

Upon opening redsn0w you will see a button that says Jailbreak. Read all the prompts after you click this button or things simply wont work (e.g. plug phone in whilst switched off…). Make sure you click “Install Cydia” on the list of options. Redsn0w will guide you through placing the phone into DFU mode and will begin the jailbreak process. At the time of writing this post redsn0w is working for iOS versions 4.3.3 and above – on the release of iOS6 it may no longer be functional.

Once the phone has rebooted an App called Cydia will be available to open. Open the app and click the manage button at the bottom. Make sure you are connected to a working Wifi network or you wont be able to do much at all.

Once in the manage section you now have the ability to add Sources by clicking on sources then pressing add. You need to add the respository repo.iparelhos.com otherwise you will not be able to download the application that unlocks the carrier restriction.

Once you have added the repository you can press the search button in Cydia and type in ultrasn0w. This is the app that you need to install, so if you can find it click on it then press install. If you cant – you may have typed the repo in wrong.

Please note if you are using iOS 5.1 or above you will also need to search for and install ultrasn0w fixer for whatever iOS version you are running.

Once the app is installed, reboot the iPhone – insert your sim card and see if you get a message saying Searching or if you get service. If you have service, congratualations you are done.

If you dont have service – dont worry this happened to me, you will need to use redsn0w again. One of the options you get upon Jailbreaking is “Install iPad baseband” – you will need to follow the process in redsn0w again however make sure that this option is ticked. Again – Read carefully the messages in redsn0w, if you dont you can severely damage your iPhone.

If you had already installed ultrasn0w and ultrasn0w fixer you should have service as soon as the phone boots up.

IMPORTANT NOTE: All iOS Jailbreaks are very dependent on the iOS version they were designed for. If you want your carrier unlock to continue to work DO NOT update your phone in iTunes. Why? – the jailbreak you are using may no longer apply to a newer iOS version which means there will be no way to unlock the phone. If you really want to try out that new iOS version make sure you have saved your SHSH blobs with Tiny Umbrella so you can downgrade to your original iOS version.