PPC and iOS compatibility

Discussion in 'PowerPC Macs' started by RedCroissant, May 20, 2015.

  1. RedCroissant Suspended

    Aug 13, 2011
    This might technically be an iOS question, but since it pertains to PPC Macs and the compatibility between them, I thought to post here.

    I would really like to upgrade my phone at some point (iPhone 3GS) and I would like to upgrade the the most recent phone that I can but still maintain full compatibility with my PPC Macs. Am I correct in my thinking that it would be an iPhone 4S running iOS 6.1.6?

    As far as I know iOS 7 isn't fully supported in OS X 10.5.8 or with iTunes 10.6.3 but I would just like some confirmation if at all possible.

    And if I am correct, is there any way to find and unlocked phone somewhere and downgrade the version of iOS?
  2. Anonymous Freak macrumors 603

    Anonymous Freak

    Dec 12, 2002
    The problem with downgrading is that almost all "reasonably current" phones can only be downgraded if you saved the SHSH blobs while the OS on it now was "the current OS."

    To my understanding, there is, for example, no way to downgrade an iPhone 5 that is currently running iOS 8 back to iOS 6, unless you had taken the measures before iOS 7 came out.

    That said, I do have an iPhone 4 still running iOS 6. But it's running stock 6.0, no updates. (Since at this point, I can't update it without going up to 7.)
  3. 128keaton macrumors 68020


    Jan 13, 2013
    Yeah, it makes me sad :(. I think running iOS 6 on my iPhone 5 was the best thing ever.
  4. MacCubed macrumors 68000


    Apr 26, 2014
    The 4S can be synced but only if it is on iOS 5


    And can't you download the firmware from felixburns or something and upgrade it that way?
  5. Anonymous Freak macrumors 603

    Anonymous Freak

    Dec 12, 2002
    I don't believe a way to do that has been found - when you attempt to "force reload" a firmware, iTunes "phones home" to check to make sure the firmware is properly signed - Apple stops signing each version soon after the next version comes out. That means any iOS older than 8.1.2 is no longer signed, and can no longer be loaded. (Really old phones/OSes - iPhone 3GS and older - are before this.)
  6. eyoungren macrumors Core


    Aug 31, 2011
    ten-zero-eleven-zero-zero by zero-two
    No offense, but your first statement is wrong.

    Simply…if it runs iOS 7 or requires a lightning cable you cannot sync it with iTunes 10.6.3. That means any iPhone 4 or 4s running iOS 6.x can sync with iTunes 10.6.3.

    The iPhone 4/4s on iOS 6 can sync with iTunes 10.6.3, but once you upgrade to iOS 7 or higher you need an Intel Mac.

    Lots of iPhone 4/4s and PowerPC owners got screwed by this when they didn't check.

    As to downgrading. No.

    The iPhone 4 and below still have an unpatched bootrom exploit that allows downgrading if you have saved blobs.

    But starting with the iPhone 4s, Apple patched the bootrom exploit. And starting with iOS 7, Apple stopped using SHSH blobs for authentication. Apple uses an entirely different process now for iOS 7 and above.


    Right. If Apple isn't signing it, you can't downgrade to it. And SHSH blobs are irrelevant since iOS 7. Doesn't matter if you have downloaded the IPSW, the only thing relevent

    Only the iPhone 4 and below which still have the bootrom exploit can be downgraded (if you have saved blobs).

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