1. elawrence033's Avatar
    I'm attempting to restore my friends iPod Touch 4G Black model so I can re-jailbreak it. The problem is, tho, that I can't restore it until I get out of recovery mode. Whenever I try to restore it while in recovery mode, iTunes gives me error 21 message, which is an unknown error. And yes, I've tried TinyUmbrella countless times but its failed every time. (If it's any help, Im using a MacBook Pro with Mac OS X Lion version 10.7.4 currently installed)


    SOMEONE HELP PLEASE!!!
    08-17-2012 07:06 PM
  2. GPAbsinthe's Avatar
    It is not an unknown error. Try and find what your problem is. Stay in recovery mode. Try and restore again.

    Apple Support :

    "Error 20, 21, 23, 26, 28, 29, 34, 37
    These errors typically occur when security software interferes with the restore and update process. Follow Troubleshooting security software issues to resolve this issue. In rare cases, these errors may be a hardware issue. If the errors persist on another computer, the device may need service."

    iTunes: Specific update-and-restore error messages and advanced troubleshooting
    08-17-2012 11:13 PM
  3. 3cit's Avatar
    I'm attempting to restore my friends iPod Touch 4G Black model so I can re-jailbreak it. The problem is, tho, that I can't restore it until I get out of recovery mode. Whenever I try to restore it while in recovery mode, iTunes gives me error 21 message, which is an unknown error. And yes, I've tried TinyUmbrella countless times but its failed every time. (If it's any help, Im using a MacBook Pro with Mac OS X Lion version 10.7.4 currently installed)


    SOMEONE HELP PLEASE!!!
    so you've used tiny umbrella to try to kick it out of recovery?
    i recommend using a different computer that hasnt had jailbreak tools on it before to try and restore it.
    08-18-2012 02:34 AM
  4. synaesthee's Avatar
    Error 21 can very commonly be a hardware issue with the device. Just as common, though, is connections to Apple's activation server may be being blocked:

    "If you have installed software to perform unauthorized modifications to your iOS device, that software may have redirected connections to the update server (gs.apple.com) within the Hosts file. You may receive an error 1004, 1013, 3194, or "This device is not eligible for the requested build" in this circumstance...."

    Even though this part of TS1275 on Apple's website doesn't reference this specific error, it might be good to check your hosts file for a blockage of gs.apple.com. If that's blocked, it can cause this issue. Usually, though, in my experience, an error 21 is a bad sign. If your hosts file looks fine on the Mac, follow 3cit's advice and try on another computer. If that fails, too, it's likely an unresolvable hardware issue with the phone. Unfortunately, sometimes they seem to work just fine until you try to restore them with the issue I'm thinking of.
    08-20-2012 11:37 AM
  5. 3cit's Avatar
    i wonder if op got this sorted.
    i had similar issues when trying to restore and i think its because alot of jailbreak programs mess with host files and that ends up causing errors, which is why i recommended using a "clean" computer with no jailbreak stuff on it. i think it would restore quick and simple that way then he can go back t his normal computer and do the deed...
    08-20-2012 04:16 PM
LINK TO POST COPIED TO CLIPBOARD