1. lornaevo's Avatar
    Last night I was trying to JB my ipod touch and when I tried loading the custom firmware it kept giving me error 21. Any one know how to get this fixed?

    HTC Evo 4G with Cm7/Wimax is Supersonic.
    04-28-2011 08:02 AM
  2. iRandom's Avatar
    Upgrade to the 4.3.2 in iTunes then jailbreak with redsn0w 0.9.6rc14
    04-28-2011 11:21 AM
  3. lornaevo's Avatar
    My firmware was already 4.3.2

    HTC Evo 4G with Cm7/Wimax is Supersonic.
    04-28-2011 12:27 PM
  4. Ipheuria's Avatar
    You didn't say what OS your computer is running so go to

    Windows: C:\Users\username\AppData\Local\Apple\Apple Software Update (You may need to have hidden folders showing to see the AppData folder Yahoo it)

    Mac: user(your user name)/library/itunes/devicesupport/

    and move the firmware files inside to an external drive or some other location on the computer. Then run Sn0wbreeze again and recreate the custom ipsw file and put your device into DFU mode. It is absolutely imperative that it is in DFU mode not recovery mode or you will get errors. If you don't know how to do it search for my username I helped someone else with the description of the process. Then in iTunes once you're in DFU mode hold down the Shift(Windows) or Option(Mac) key and click restore. Then browse to the custom ipsw you made with Sn0wbreeze and let it reload.
    04-28-2011 01:04 PM
  5. SnapThrow's Avatar
    After a Google search for "iPhone error 21" which returned several pages related to the problem (you did try that right?) it seems that this error is related to a communication problem between your iPhone and your computer. You didn't provide any details for your setup, but you could try using a different computer or profile, or maybe even a different USB port to jailbreak your iPhone.
    04-28-2011 01:06 PM
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