Create Custom iOS 6 Firmware to Preserve iPhone 4 or 3GS Baseband with Redsn0w 0.9.15b2

Many people relying on iPhone unlock have been waiting for new version of Redsn0w in order to upgrade their iPhone 4 or 3GS to iOS 6 with the ability to preserve their device baseband. Well you don’t need to wait any longer because Redsn0w 0.9.15b2 is here which will create custom firmware for you in a few easy steps.

Below we are going to guide you through the whole process of creating custom IPSW for iOS 6. Our readers who have done this process number of times might not need this guide but still it can help you in case you missed any step. People who are doing this for the first time will definitely find this tutorial handy.


1. Download latest Redsn0w 0.9.15b3 for Windows or Mac.

2. Download iOS 6 IPSW file for iPhone 4 or 3GS.

3. Extract the file you downloaded in Step 1 and run Redsn0w.

4. Head over to Extras > Custom IPSW and locate the iOS file you downloaded in second step. If you’ve iPhone 3GS then you’ll be required to tell the program that whether your device has a old or new Bootrom.

5. Now give Redsn0w some time to cook custom firmware file for you. Once the file is created, find it in the same folder where stock iOS 6 file is located. The file name will start with “NO_BB” prefix.

Update: People who are stuck at step 5 due to “couldn’t find 6.0(10A403) blobs for this device on the apple or cydia servers” error, please use the help given at this link.

6. In order to use this IPSW your phone should be in DFU mode. Connect your phone the Computer. Go to Extras > Pwned DFU and follow the on-screen instructions to enter into DFU mode.

7. After successfully doing sixth step, run iTunes and use Shift+Restore on Windows and Option+Restore on Mac to update your iPhone with custom firmware. Make sure that you select the file with with “NO_BB” prefix.

8. If your phone is stuck on Apple logo because of tethered jailbreak then use “Just Boot” option in Redsn0w to bypass it. You can find this option in Extras.

9. Now you can use Ultrasn0w fixer to unlock your device on iOS 6. You can find Ultrasn0w fixer guide here.