Downgrading iOS 4.2.1 to 4.1, 4.0.2, 4.0.1 on iPhone, iPod touch and iPad

With the release of iOS 4.2.1, many iPhone, iPad and iPod users upgraded to it. But as Cydia is still broken so jailbreaking does not makes sense. Here is a guide that will help you in downgrading back to 4.1, 4.0.2, 4.0.1.

Steps:

First of all, you need to have “SHSH blobs” for the firmware to which you are intending to downgrade.

  • Download the files of ipsw firmware.
  • Put your iPhone, iPad or iPod in DFU mode instead of recovery mode.
  • Locate host files by navigating to C:\Windows\System32\drivers\etc\
  • Use Notepad to open the host file. Add the following command 74.208.105.171 gs.apple.com

Now to restore the iPhone, iPad or iPod to the firmware, do the following:

  • Hit the iOS device icon on the sidebar of the iTunes while holding left Shift button in Windows and left Alt button in Mac. Click Restore and release the button.
  • On prompt from iTunes, select the ipsw file and click Open. This will let the iTunes to start the process.
  • Once iTunes is finished with the process, download Tiny Umbrella. Launch it and click Exit Recovery Mode to exit from it. This will let your device start normally. Now your device is ready to be jailbreak.