Preserve Baseband Upgrading to 5.1.1

iPhone Dev Team’s latest release of Redsnow can help Ultrasnow Unlock and Gevey Sim users to preserve their unlockable baseband using custom ipsw file . These .ipsw files can be stitched with the shsh blobs during the jailbreaking process . If you have the basebands that support Ultrasn0w and Gevey Sim unlock follow the steps below for upgrading while preserving baseband using No BB ipsw. First upgrade to custom 5.1.1 ipsw and the jailbreak followed by Ultrasn0w Unlock . All details explained below .

Steps to Upgrade to 5.1.1 using Custom IPSW to Preserved Baseband :

  1. Download Redsn0w 0.9.11b4 on your Mac or Windows PC
  2. 5.1.1 custom ipsw baseband preservation Redsn0wLaunch Redsnow and click on Extras .
  3. Now select Custom IPSW as shown in the image above and browse to the iOS 5.1.1 .ipsw firmware file to create a No BB file . If you have an iPhone 3GS, you will be prompted whether you have an old or new bootrom. Select the right one
  4. Redsnow will now create the custom 5.1.1 ipsw file with No BB added to its file name . This is to indicate the .ipsw carrier no baseband details and hence will not upgrade your baseband which usually locks phone’s.
  5. Now put your iPhone 4 to PWNED DFU mode . This can be done by going into Redsnow > Extras > Pwned DFU
  6. Now connect your device with the computer and launch iTunes . Itunes will detect the connected device
  7. On iTunes press SHIFT + Restore or ALT+Restore on a Mac computer . Select the 5.1.1 ipsw with No BB on it . Making a mistake here will permanently upgrade your firmware , so it is a good idea to double-check the file you are selecting .
  8. Itunes will now verify the firmware file and update your device . Ff you face Error 3194 , edit the hosts file as explained here .
  9. After the upgrade is complete you can jailbreak iPhone 4 on 5.1.1 following the tutorial explained here .
  10. Install UltraSn0w Unlock on 5.1.1 using the UltraSn0w Fixer

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