iPhone Dev Team released Ultrasn0w 1.2.4, brings iPhone 4 and iPhone 3GS Unlock on iOS 5 . Ultrasn0w 1.2.4 on New Basebands are not supported, so Preserve iPhone 4 Baseband to Unlock iOS 5 iPhone 4/3GS with Ultrasnw0 1.2.4 .
Unlock iOS 5 On iPhone 4, iPhone 3GS Using Ultrasn0w 1.2.4 Or Gevey SIM on Supported Basebands: 01.59.00 for iPhone 4 and 04.26.08 / 05.11.07 / 05.12.01 / 05.13.04 / 06.15.00 for iPhone 3GS. If your iPhone 4 on baseband 01.59.00, you’ll need to preserve your iPhone 4 baseband to prevent upgrading to higher baseband in order to get your unlock on iOS 5 or users who rely on unlock on iOS 4.x.x and need to upgrade to Apple’s new software, iOS 5. Preserving iPhone 4 BASEBAND is so important to keep Unlock.
Follow these Required Steps to Preserve iPhone 4 Baseband while Upgrading to iOS 5.
How to Preserve iPhone Baseband
First you need to Download iOS Final from HERE, iTunes 10.5 for Windows and Mac and Redsn0w 0.9.9b5 FROM here. Follow the Given Guide to Preserve iPhone 4 Baseband.
Step 1 – Connect your iPhone 4 to the Computer via USB Cable and Open Redsn0w 0.9.9b5 (Mac Only).
Step 2 – Now Only Select Extras and then “Custom IPSW” Option, to create your Pre-Jailbroken Custom Firmware.
Step 3 – Redsn0w will now start cooking your Custom IPSW, in few minutes into your hand.
Step 4 – Once you get your firmware, select ‘Pwned DFU’ from RedSn0w
Step 5 – Now Follow the on-screen Instructions to get your iPhone into DFU Mode.
Step 6 – Once iPhone in DFU Mode, close Redsn0w and Point iTunes 10.5 to your iPhone 4 Custom iOS 5 IPSW which begins with NO_BB. (WARNING: Don’t select the stock one or you’ll lose your unlock).
Thats it you have Successfully Preserved iPhone 4 Baseband and now you can Unlock iPhone 4 on iOS 5 using Ultrasn0w 1.2.4 .