How to unlock your iPhone 4 or 3GS running on iOS 4.3.1 using ultrasn0w 1.2
Time for a new tutorial on how to unlock your iPhone 3gs or 4 running 4.3.1 firmware. Unlocking is technically reversible so you don’t have to worry about voiding your warranty too much. If your phones start acting weird you can restore it through iTunes and send it to be repaired, but only if you actually can restore it, that is, if it works to the point that it can be restored. Legally, you can unlock your phone, it is not protected under the DMCA agreement but it can void your warranty if the seller finds out. Also important to note is the fact that some carriers have no problem with unlocking, to be sure just call them and ask. Some even unlock the phones themselves for a fee.
Unfortunately things aren’t as straightforward as they may seem. The tool we are going to be using only works for a selected number of basebands. What is a baseband you may ask? It can be described in the simplest way just by using two words: modem firmware. And now you get that funny feeling when you find out about a thing you didn’t know you knew. This phrase was made famous by Donald Rumsfeld by the way! Going back on topic, your phone actually has a wireless modem that is uses to connect with the carrier through antennas placed outdoors. My guess is that the carriers fiddle with the baseband versions to prevent users from unlocking their phones, thus forcing them to use only their services.
So, your phone needs to be running one of the old basebands in order to successfully unlock your 4.31 iPhone 4 or 3GS. To check which baseband you have just to go to Settings -> General -> About and make sure you have one of these basebands:
- 01.59.00
- 04.26.08
- 05.11.07
- 05.12.01
- 05.13.04
- 06.15.00
Note: While this is not mandatory or required it would be good if you can sync and backup your iPhone with iTunes to make sure you’ll save all your important data (photos, music, documents, settings and contacts)
Step 1. First thing’s first, your phone must be Jailbroken in order to do this. Use redsn0w or pwnagetool to jailbreak your iPhone running on 4.3.1
Step 2. After your iPhone has been jailbroken go ahead and launch Cydia.
Step 3. Do a search for ultrasn0w 1.2.1 . If you cannot find it you will have to add it manually. But don’t fear because this is a no-brainer. If it’s there just skip to step 5.
Step 4. Just go to Manage, then Sources and tap on Edit and then on Add. After this write down the following URL http://repo666.ultrasn0w.com
Step 5. Install Ultrasn0w 1.2.1. After it’s finished installing please reboot the phone and gaze at your unlocked iPhone.
