Downgrading to iOS 6 on an iPhone 5S?

Discussion in 'iOS 7' started by Norcal., Jun 13, 2014.

  1. Norcal. macrumors regular

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  2. Nermal Moderator

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    #2
    Nope. It lacks the necessary drivers, and even then you can't install it due to Apple's signing system.
     
  3. Altemose macrumors G3

    Altemose

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    #3
    On top of that the kernal probably has no clue what to do with the A7.
     
  4. Quantum2 macrumors newbie

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    #4
    The main problem would be that Darwin 13.0 is not compiled to 64 bits (neither are the drivers on that version)
     
  5. Altemose macrumors G3

    Altemose

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    #5
    Historically, a 32 bit OS can run just fine on a 64 bit processor, though can't address more than 4 GB of RAM or use the 64 bit CPU to its potential. Just look at Windows XP running on Core 2 Duo PCs. I am not sure how that would hold to iOS.

    Though, in summary it isn't going to ever work without serious modifications to the firmware and falsifying the signing process. That is a lot of work that I think only Apple could really achieve since it is their process and code. Working off of someone else's code is a royal nightmare.
     
  6. AxoNeuron macrumors 65816

    AxoNeuron

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    #6
    Why on earth would someone ever do this...?

    Some people SERIOUSLY don't like change.
     
  7. Quantum2 macrumors newbie

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    #7
    That's because most 64 bit processors emulate 32 bits (x86-64 architecture), but I'm not sure if the 5S processor has that capacity, but I agree with you, in our end it would be almost impossible getting a 5S to run iOS 6
     
  8. Intell macrumors P6

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    #8
    The 5S' A7 does have 32-bit emulation. Otherwise it wouldn't be able to run older iOS apps that are not 32/64-bit or 64-bit binaries. The thing that would hang it up is the bootrom. It wouldn't properly initialize the hardware for a 32-bit OS.
     
  9. Quantum2 macrumors newbie

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    #9
    That doesn't mean it can run a 32 bit kernel, windows can run 32 bit apps by using WoW64 (http://en.wikipedia.org/wiki/WoW64).

    The apps themselves only need to be rewritenn if they use kernel level functions
     
  10. The Doctor11 macrumors 603

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    #10
    Absolutely impossible. There was never a iOS 6 version for iPhone 5s so its just impossible.
     
  11. Quantum2 macrumors newbie

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    #11
    Nothing is impossible, as it was already stated, the only big issue would be dealing with the different CPU architecture, and lack of drivers, but remember that the Darwin kernel is exactly the same used in Mavericks so it should be "easy" (read possible) to compile it to ARM, and for the lack of drivers, it's a pain in the ass, but it's the same difficulty as making drivers for OS X to run on Windows machines and that has been done for years for a multitude of devices.

    In short, it would be very difficult, but nonetheless possible
     
  12. The Doctor11 macrumors 603

    The Doctor11

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    #12
    Well close enough to impossible. And you would completely lose the touch ID
     
  13. Altemose macrumors G3

    Altemose

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    #13
    No. A developer looking to put iOS 6 on a 5S would have to code in Touch ID into the software. This is kind of a dead topic, it just never is going to come to fruition.
     
  14. Intell macrumors P6

    Intell

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    #14
    The kernel would execute, but it won't initialize due to the bootrom not giving a 32-bit only kernel a proper starting point.
     
  15. sunking101 macrumors 603

    sunking101

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    #15
    The limitations are moot because there isn't even any way of putting iOS6 onto an iPhone 4 now! Not unless you have a 'blob' or are prepared to put a possibly tampered with and unsecure o/s sourced from the net onto your phone.
     
  16. lovewd macrumors 6502

    lovewd

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    #16
    This is like asking if there is a way to put iOS 4 on the iPhone 5
     
  17. I7guy macrumors G5

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    #17
    While you can install a 32 bit O/S, such as XP on a 64 bit machine, you can't install a 64 bit O/S on a 32 bit processor. Try it and see.

    Although Windows is a bit different as Windows XP for example, won't know about newer processors, but it will install anyway on any processor as Intel builds their new processors to be 100% compatible through the generations.

    And while I don't specifically know how IOS identifies processors, IOS 6 probably doesn't have the smarts to work with the A7, and who knows if the A7 can even be booted in 32 bit mode. Not to mention the signing of the IOS operating system.
     
  18. Altemose macrumors G3

    Altemose

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    #18
    Intell stated that the A7 can do full 32 bit emulation in order to run older apps not using the new 64 bit architecture. That being said, the boot loader would not initialize the 32 bit kernel properly.
     
  19. C DM macrumors Westmere

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    #19
    Even if you could get through all of that there's no signed version of the firmware to install so there wouldn't be a way to install it on the phone even if you had something that could be compatible.
     
  20. Paddle1 macrumors 68030

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    #20
    iOS 6 could easily be made to run on the 5S if Apple wanted it to. If they can force iOS 7 onto the 4, they can update 6 to work on the 5S.

    Otherwise the signing is the first thing you would have to worry about anyway.
     
  21. Dented macrumors 6502a

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    #21
    But why on earth would or should they spend even a nanosecond working on such a thing? I'm sorry but if you bought a 5S, you bought a phone that runs IOS 7, end of story; you have absolutely no excuse for whining about IOS 6 if you paid Apple for a phone that has only ever run IOS 7.
     
  22. richwoodrocket macrumors 68020

    richwoodrocket

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    #22

    Nothing is impossible is the biggest lie I've ever heard.
     
  23. I7guy macrumors G5

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    #23
    I guess then you might as well build your own phone since "nothing is impossible". All it takes is time, money and knowledge. #
     
  24. Altemose macrumors G3

    Altemose

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    #24
    And write your own operating system with a network of app developers...
     

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