How To Downgrade iOS 4.3 to iOS 4.2.1, iOS 4.1 on iPhone, iPod and iPad

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If you have upgraded your iPad, iPhone 4, iPhone 3GS or iPod Touch 4G/3G to iOS 4.3 for testing purpose and now you are facing any issues with your favourite apps on this new release or you want to downgrade your device to jailbreakable iOS 4.2.1 / iOS 4.1, here is complete step by step guide to downgrade iOS 4.3 to previous iOS versions.
This downgrade process is only for those who have saved SHSH Blobs to Cydia servers for iOS 4.2.1 and iOS 4.1 and we hope you all have done so.


If you are still on iOS 4.2.1, we highly recommend you to save the blobs before upgrading iPhone to iOS 4.3. You can either use TinyUmbrella on Windows and Mac Systems or iSH**** app on your iPhone.
Steps to Downgrade iOS 4.3 to iOS 4.1 or iOS 4.2.1:
Step 1: Download the required IPSW firmware you want to restore on your phone.
Step 2: Open”Hosts” file in NotePad from this location in Windows OS: C:/WINDOWS/system32/drivers/etc

If you are Mac user, navigate to GO -> Go to Folder and enter the path “/etc” and open the file “hosts” with TextEdit.
Step 3: Now add the following hostname at the end of the file as shown in the screenshot below. Save the file.

74.208.105.171 gs.apple.com

Step 4: Open iTunes and connect your device with the PC via USB cable and put your device into DFU mode. Here is how you can get DFU mode on your phone.

• 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).

Step 5: From the iTunes sidebar select your device. Now press the “alt” (option) button on Mac or left “Shift” button if you are on Win and then click on “Restore” button in the iTunes.

This will make iTunes prompt you to select the location for iOS 4.2.1 or iOS4.1 you downloaded in step 1.
Now sit back and let iTunes restore iOS 4.2.1 or your iPhone/iPad/iPod Touch. During the restore process you may see unknown error messages (1013, 1004 etc), just ignore these errors.
At this point your iPhone may be stuck in recovery mode, showing that “Connect to iTunes” screen. To get rid of this recovery mode, download TinyUmbrella and click on “Exit Recovery” option.
That’s all. Now you can use the software mentioned here (tethered jailbreak) or here (untethered) to jailbreak your iPhone.
Downloads:

• Download iTunes 10.1.x
• Download iOS 4.2.1
• Download TinyUmbrella
• Download iOS 4.1