Update 3GS with iOS3 to iOS4?

Discussion in 'iOS 5 and earlier' started by vkping, Aug 23, 2012.

  1. vkping macrumors newbie

    Aug 23, 2012

    We purchased an iPhone 3GS to test our iOS software on an older device.
    The 3GS has currently iOS 3.1.3 installed.
    I would like to upgrade it to iOS 4.2.1 since this is the minimum version we support. I found the correct .ipsw, but restoring / upgrading fails with the message "this device isn't eligible for the requested build".
    Apparently there is some sort of code signing in place which prevents my device from being upgraded to anything other than iOS5.1.

    I googled a while, but while that error message is pretty common, I couldn't find a solution to my particular problem: To restore a device from iOS3 to iOS4 while there is an iOS5 update available.

    Is there any way to "officially" install iOS4 on the device? I don't think that jailbreaking would be a solution for us, we would like to have a device which is as close to a typical iOS4 user as possible...
  2. DerekRod macrumors 6502a


    Jan 18, 2012
    If apple is no longer signing iOS 4.2.1 it is impossible unless you have saved SHSH blobs for that device

    Edit:They are still signing it but only for the iPhone 3G
  3. goosnarrggh macrumors 68000

    May 16, 2006
    If you're a registered developer, perhaps you may find some help contacting the Apple Developer Connection technical support.

    I suspect, though, that their first recommendation would be that you should focus any new development effort only on the newest iOS available for each generation of device you intend to support.
  4. alphaod macrumors Core


    Feb 9, 2008
    Last time I checked they were still signing for the 3GS as well.

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