Cannot Restore iPod Touch to Older OS for Testing?

Discussion in 'iOS Programming' started by ArtandStructure, Sep 10, 2009.

  1. ArtandStructure macrumors member

    Joined:
    Jan 14, 2008
    Location:
    Klamath Falls, Oregon
    #1
    Hello all.


    Has anyone successfully restored their iPhone or iPod Touch from OS 3.0 back to OS 2.2.1 in Xcode's Organizer?

    I have a game just about ready to go which had worked in 2.2.1 but when I upgraded to 3.0 it had a few issues. I've since resolved those issues in 3.0 and now want to restore back to 2.2.1 to test the new code. However trying to do so in Organizer gives the following error, "ERROR: Cannot restore older epoch without using DFU". I had been in contact with an Apple engineer regarding my OS 3.0 issues and asked him how to restore back to 2.2.1 for testing. He replied he is not sure and has never "been able to obtain guidance on this in past requests".

    Why is there an option to restore back to an older version if it isn't possible? I can understand this policy for consumers (unless the new OS is terribly flawed) but as far as providing the best service and experience to the customer, being able to test multiple OSs is essential as a developer.

    So again, has anyone been able to do this or encountered and overcome this error?


    Many thanks for any assistance,


    Jesse Widener
    Art and Structure
     
  2. dejo Moderator

    dejo

    Staff Member

    Joined:
    Sep 2, 2004
    Location:
    The Centennial State
    #2
    The list of valid restore images is stored in:

    Home Folder > Library > iTunes > iPod/iPhone Software Updates

    Put the .ipsw for the version you want into this folder and you will be able to use Xcode to restore to it. If you don't have the desired .ipsw file, search around the 'net; I'm sure you can find one. Why Apple doesn't provide easy access to previous OSes confuses me but I suppose they expect you to download and save them as they go along because the old version disappears as soon as the new version is released.
     
  3. ArtandStructure thread starter macrumors member

    Joined:
    Jan 14, 2008
    Location:
    Klamath Falls, Oregon
    #3
    Thank you for the response.

    In the folder you suggest I already have iPod2,1_2.2.1_5H11a_Restore.ipsw and iPod2,1_3.0_7A341_Restore.ipsw which I read as the 2.2.1 and 3.0 .ipsw files respectively. A site I found for downloading these seems to confirm this. I still get the error. Any other suggestions?


    Many thanks,


    Jesse Widener
    Art and Structure
     
  4. jnic macrumors 6502a

    Joined:
    Oct 24, 2008
    Location:
    Cambridge
    #4
    So put your device into DFU mode :)
     
  5. ArtandStructure thread starter macrumors member

    Joined:
    Jan 14, 2008
    Location:
    Klamath Falls, Oregon
    #5
    Thank you!

    It worked, though not quite as the article and several others I read suggested. While their methods apparently worked flawlessly for them, iTunes kept giving me an error (20) when trying to restore. However the DFU mode part worked and restoring via Xcode's Organizer worked after having to "restore" twice; the first time changes the iPod from a "black" screen to a "white" screen. The second "restore" finishes the job.


    Again many thanks,


    Jesse Widener
    Art and Structure
     

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