How to perserve baseband and restore to an old firmware?

Discussion in 'Jailbreaks and iOS Hacks' started by doc2142, Nov 17, 2011.

  1. doc2142 macrumors member

    Joined:
    Jul 17, 2010
    #1
    I have an iphone 3gs 4.0.1 firmware. It is starting to crap on me so I need to upgrade it either to 4.0.1 again or maybe to 4.2.1. It is jailbroken right right now and unlocked on the 5.13 firmware I believe. Its the one where it doesn't screw up your gps. I would like to upgrade to 4.2.1 while preserving the baseband. How would I go on to do this? I know I will need to use a program to preserve my baseband and another one to allow me to upgrade a ipsw that is old. (I do believe I have the SHSH saved in surik server since this phone was jailbroken for about a year)
     
  2. ylerT macrumors regular

    ylerT

    Joined:
    Jun 10, 2011
    Location:
    Las Vegas
    #2
    To restore to a certain version you need to make sure you have the SHSH files saved. The easiest way to know for sure is to download TinyUmbrella and check for what Cydia has on file for your device. If you have the old bootrom you can even update to iOS 5 while preserving your baseband and remain untethered.

    To create a custom firmware you need to use either sn0wbreeze (PC) or pwnagetool (Mac). Depending on what iOS version you decide to go with and can actually restore to, you may need to use TinyUmbrella again to point iTunes to Cydia's servers.
     

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