Recently, Apple has just Released iOS 4.3.1 for iPhone 4, iPhone 3GS, iPod touch 3G, iPod touch 4G, iPad 2, and iPad.
Download it from here:-
How to Downgrade your iOS 4.3.1 iDevice
Note -You must have SHSH blobs saved for the iOS you want to downgrade to.
But Before downgrading your iDevice Also Read if You have any Doubt About these:-
How to Jailbreak iPhone 4 iOS 4.3.1 Using PwnageTool
Steps To Follow:-
1. Download the IPSW of iOS you want to downgrade to.
2. For Windows Users– Navigate to the following folder “C:WindowsSystem32driversetc”
Mac OS X users — Go to “/etc/” directory by going through “Go –> Go to Folder” from Finder.
3. Now you need to find the hosts file in Note pad if using Windows and in TextEdit if you are a Mac User.
4. Now you need to Put your Device into DFU mode.
Steps To Put Phone Into DFU Mode:-
- First,Turn off your phone.
- Now press Power button and as soon as you seen Apple Logo, press Home button while keeping pressed Power button too.
- Keep holding down both button for about 10 seconds.
- After 10 sec, release Power button but keep holding Home button until iTunes recognizes your iPhone. You should keep the PC volume high to hear New Device Detection sound.
- Let go the Home button. At this point your iPhone screen should be blank (black in color).
5. Now run itunes software and let it detect your iphone once detected you will get an alert “iTunes has detected an iPhone in recovery mode. You must restore it before it can be used.” Click okay.
6. Press “SHIFT” key windows users/ “ALT” key Mac users and click on “Restore“
7. That’s it.!!!
In case you get a error message 10XX, Dont worry,Your restore might have successfully completed. But you need to get your iPhone out the recovery mode.



