1. jeff-4's Avatar
    I am a bit confused about SHSH and signing. I realize that the SHSH blob must be saved to go back or restore older iOS (using TU and Pwanage Tool). How about the following case?

    If I have a 3GS with older iOS and unlockable Baseband (05.12.01 or 05.13.04) that has no saved SHSHs, can I currently use PwnageTool to build a custom 4.2.1 and safely update the phone (preserving the baseband to unlock with ultrasn0w)?

    Hope this is not too dumb a question to get a good answer!
    2011-08-20 05:54 AM
  2. Mes's Avatar
    ....If I have a 3GS with older iOS and unlockable Baseband (05.12.01 or 05.13.04) that has no saved SHSHs, can I currently use PwnageTool to build a custom 4.2.1 and safely update the phone (preserving the baseband to unlock with ultrasn0w)?...
    Unfortunately no!

    SHSH blobs are required to load any non-current version ..........

    except 4.1. Why only 4.1? Apple is currently signing 4.1 for 3G/3GS. Strange but true

    Keep in mind, if you pick 4.1, a custom firmware w/PwnageTool is still required to preserve the baseband and unlock.

    ..... I just remembered a fairly new option .... it's called iFaith.

    Using your currently running iPhone on 4.2.1, iFaith can create 4.2.1 SHSH blobs.
    Optionally, iFaith will use these and create a pre-signed 4.2.1 firmware with no baseband update too
    A pre-signed firmware doesn't need TU or any SHSH blobs.

    With this option, you can reload this special iFaith 4.2.1 anytime
    Last edited by Mes; 2011-08-20 at 06:26 AM.
    2011-08-20 06:02 AM
  3. jeff-4's Avatar
    Unfortunately no!

    ..... I just remembered a fairly new option .... it's called iFaith.

    Using your currently running iPhone on 4.2.1, iFaith can create 4.2.1 SHSH blobs.
    Optionally, iFaith will use these and create a pre-signed 4.2.1 firmware with no baseband update too
    A pre-signed firmware doesn't need TU or any SHSH blobs.

    With this option, you can reload this special iFaith 4.2.1 anytime
    But isn't this a bit of a catch-22? My cursory reading of iFaith says it save the SHSH blob of the current firmware version of the iPhone. So, for example, if I'm running 3.1.3 it will save its SHSH blob, but not the SHSH for 4.2.1. Can I then upgrade from, say 3.1.3 to 4.2.1 without the 4.2.1 SHSH blob?
    2011-08-20 07:36 AM
  4. Mes's Avatar
    I would use iFaith as a 'second' option, not the primary one.

    Say for instance I pick up a 3GS currently on 4.3.3 w/no SHSH blobs.
    If I use iFaith while it's on 4.3.3, I can build a pre-signed 4.3.3 firmware and then re-load 4.3.3 anytime I want.

    TU on the other hand, will only get the 'currently Apple signed' SHSH blobs .... 4.3.5.

    When a new phone has OLD firmware, it saves the ability to reload that OLD firmware

    Upgrading, downgrading, etc have not changed, just the individual iOS version options.
    Last edited by Mes; 2011-08-20 at 07:44 AM.
    2011-08-20 07:42 AM
  5. jeff-4's Avatar
    OK. Thank you. So, it looks as if I right now I could only go to iOS 4.1 for upgrading (preserving the baseband). Unless or until the iDev team can crack the iOS currently being signed, then I can go forward again, correct?

    Unfortunately no!

    SHSH blobs are required to load any non-current version ..........

    except 4.1. Why only 4.1? Apple is currently signing 4.1 for 3G/3GS. Strange but true
    Hey, Mes. Since you are so helpful, is Apple currently signing any older iOS versions for the iPhone 4?
    Last edited by jeff-4; 2011-08-20 at 07:57 AM.
    2011-08-20 07:53 AM
  6. Mes's Avatar
    4.1 is an option..... but you missed the second part .... your current 4.2.1 is also an option

    ..... I just remembered a fairly new option .... it's called iFaith.

    Using your currently running iPhone on 4.2.1, iFaith can create 4.2.1 SHSH blobs.
    Optionally, iFaith will use these and create a pre-signed 4.2.1 firmware with no baseband update too
    A pre-signed firmware doesn't need TU or any SHSH blobs.

    With this option, you can reload this special iFaith 4.2.1 anytime
    FYI: As of this moment, Apple is signing 4.3.5 and 4.1.

    You have one more option: 4.2.1 because you phone is running 4.2.1

    Note: Both methods will preserve the baseband and your unlock
    Last edited by Mes; 2011-08-20 at 08:11 AM.
    2011-08-20 08:02 AM
  7. jeff-4's Avatar
    Wait, do you mean I could use iFaith with an existing 4.2.1 phone to create a pre-signed, custom 4.2.1 firmware (that does not upgrade the baseband) that could be loaded into a *different* phone (i.e., the one with an older iOS but no SHSH blob for 4.2.1)? If so, this would be a very interesting option!

    Any idea about iPhone 4 Apple signing practices?
    2011-08-20 08:22 AM
  8. Mes's Avatar
    Wait, do you mean I could use iFaith with an existing 4.2.1 phone to create a pre-signed, custom 4.2.1 firmware (that does not upgrade the baseband) that could be loaded into a *different* phone (i.e., the one with an older iOS but no SHSH blob for 4.2.1)? If so, this would be a very interesting option!

    Any idea about iPhone 4 Apple signing practices?
    Not a different phone, the same phone. Just like Tiny Umbrella's SHSH blobs are device + iOS version unique.

    What I'm saying is this: If something happened to your phone tomorrow and you needed to restore, today you might assume you can only load 4.1 or 4.3.5, right?

    If now, right now, you created a 4.2.1 iFaith SHSH blob and firmware .... tomorrow you would have 3 valid restore options: 4.1, 4.2.1, and 4.3.5.

    To me this is a fascinating new option. If I have a choice, 4.2.1 is better than 4.1 any day of the week
    Last edited by Mes; 2011-08-20 at 08:33 AM.
    2011-08-20 08:28 AM
  9. jeff-4's Avatar
    Thanks for clarifying this!
    2011-08-20 08:34 AM
  10. Mes's Avatar
    You're quite welcome.

    iFaith is relatively new and received very little news and guides.
    It's a great tool for some (maybe many), with old installed firmware and no saved SHSH blobs.
    2011-08-20 08:37 AM
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