How to unlock your iPhone 4 (01.59.00) running on iOS 5.0.1 using ultrasn0w 1.2.5
With the release of the new version of Ultrasn0w 1.2.5 , now you can unlock your jailbroken iPhone 4 running iOS 5.0.1. 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.
It is worth mentioning that this is only for phones running on the 01.59.00 baseband. If your phone is not running on this baseband then you cannot unlock it. You may or may not know what a baseband is, but for those who are not well familiarised with the iPhone community lingo I shall explain. Stored inside your phone there is a wireless modem that sends and receives data, it basically communicates with your carrier and allows you to use it well… to use it as a phone. This modem has a specific firmware version that can be changed by Apple. The probably change the version once very now and then to prohibit their users from unlocking it.
To check which baseband you have just to go to Settings -> General -> About and look at the field entitled “Modem Firmware”” as show in the picture below.
Note: In order to unlock your iPhone 4 on the iOS 5.0.1 firmware then you must first have to update to iOS 5 through a custom IPSW created using RedSn0w 0.9.9b5. Caution: Do not update the to the stock iOS5 as this will also update your baseband.
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. Firstly, your phone must be Jailbroken in order to do this.
Step 2. After your iPhone has been jailbroken go ahead and launch Cydia.
Step 3. Do a search for ultrasn0w 1.2.5. If you find it there then proceed to step 6, If not then you have to add it manually. But don’t fear because this is really easy to do. Proceed to step 4.
Step 4. Just go to Manage , then Sources
Step 5. Tap on Edit and then on Add. After this write down the following URL http://repo666.ultrasn0w.com
Step 6. Install Ultrasn0w 1.2.5 by clicking install and then confirm
Step 5. Once UltraSn0w is installed you must restart your iPhone 4 and run RedSn0w to boot tethered, you’re done!
