How To Downgrade From iOS 5.1 To iOS 5.0.1 / 5.0 / 4.3.3 / 4.3.5 For iPhone 4, 3GS, iPod Touch 4G, 3G iPad 2 & iPad

Well, after releasing iOS 5.1 there was a very important question, this question was how to downgrade from iOS 5.1 to " iOS 5.0.2 / iOS 5.0.1 / iOS 5.0 or iOS 4.x " ? in case you are not satisfied from iOS 5.1 or updated your iDevice to check the new features founded in iOS 5.1 or updated your device mistakenly, it’s certainly you lost your untethered jailbreak. These are some probability, So we will show you how to downgrade from iOS 5.1 to any older version of firmware in this post after the jump.

Before showing you how to downgrade your iPhone, iPad or iPod touch let’s divide them into two groups, the fist one is the non-A5 devices (iPhone 4, 3GS, iPad 1, iPod Touch 4G, 3G), the second one is the A5 devices (iPad 2 and iPhone 4S).

Non-A5 devices (iPhone 4, 3GS, iPad 1, iPod touch 4G, 3G):

Downgrade from iOS 5.1 to 5.0.1 / 5.0 can only be held via custom firmware only.
Downgrade from iOS 5.1 to 4.3.5 / 4.3.4 / 4.3.3 / 4.x can be held via stock firmware.
You MUST have saved SHSH blobs for the firmware you downgrading to.

A5 devices (iPhone 4S / iPad 2):

iPhone 4S can’t be downgraded from 5.1 to 5.0.1 / 5.0 even you have the save SHSH blobs for them, here’s what iPhone Dev-team said in their blog:

If you have an iPhone 4S, the basic rule above is really the only rule: you cannot restore back to 5.0.1 once the 5.0.1 signing window is closed, no matter what (even if you saved your SHSH blobs).

iPad 2 can’t be downgraded from 5.1 to 5.0.1 / 5.0 even you have saved SHSH blobs for them. iPad 2 users can only downgrade from 5.1 to 4.x (4.3.5, 4.3.4, 4.3.3 … etc) in case you have saved SHSH blobs for the firmware you downgrading to.

If you have an iPad2 with saved 4.x hashes, you can in fact downgrade to that 4.x but you won’t be able to get to 5.0.1 once the 5.0.1 signing window is closed (even if you saved your 5.0.1 SHSH blobs).

How to downgrade 5.1 to 5.0.1 / 5.0 – iPhone 4, 3GS, iPad 1, iPod touch 4G, 3G:

Requirements:

Saved SHSH blobs for the firmware you download to (5.0.1 / 5.0)
Download iFaith for Windows
Download iTunes – Windows / Mac
Download iOS 5.0.1 or iOS 5.0 for your iDevice

Step 1: Run iFaith, and choose “Build *signed* IPSW w/Blobs” > “Build IPSW”

downgrade 5.1 to 5.0.1 / 5.0 / 4.3.3 iPhone 4, 3GS, iPad 2, 1, iPod touch

Step 2: Now browse the saved SHSH blobs file for iOS 5.0.1 / 5.0.

Step 3: Now browse for the ipsw file of iOS 5.0.1 / 5.0

Step 4: iFaith will cook the custom firmware of 5.0.1 / 5.0 with SHSH blobs.

Step 5: Now from iFaith choose “Use DFU Pwner (iREB)”

Step 6: Finally open iTunes and restore your iDevice to the new custom firmware, that’s it.

How to downgrade 5.1 to 4.3.3 / 4.3.5 or 4.x – iPhone 4, 3GS, iPad 2, 1, iPod touch 4G, 3G:

Saved SHSH blobs for the firmware you gonna downgrade to (4.3.3 / 4.3.5 / 4.3.4 … etc)
Download Redsn0w – Windows / Mac
Download iOS 4.3.5 / 4.3.4 / 4.3.3 (Download only the firmware you gonna downgrade to)
Download iTunes – Windows / Mac
Download TinyUmbrella – Windows / Mac

Step 1:Once you’ve downloaded the required IPSW file, its time you put your iPhone, iPad or iPod touch into DFU mode. Open Redsn0w > Extras > Pwned DFU.

Step 2: Here comes the tricky and the most important part, you’re going to fool iTunes into thinking that its in contact with Apple’s servers, whereas we’re going to change that to Saurik’s server. In order to do this, follow the steps given below:

For Windows Users:

Navigate to C:\Windows\System32\drivers\etc\ and locate the file named as “hosts”.

For Mac Users:

Mac users can access the “hosts” file by navigating to “/etc/” folder, which can be found through Go > Go to Folder from within Finder.

If you’re on Windows, then open the “hosts” file in Notepad. If on a Mac, then open the “hosts” file in TextEdit, and add the following line at the end:

74.208.105.171 gs.apple.com

Step 3: Launch iTunes, the select your devices from the left sidebar, then Hold down Shift (Win) or Alt (OS X), click Restore then refer iTunes to iOS 4.3.3 / 4.3.5 / 4.x.x (Firmware you gonna downgrade to)

Step 4: In some cases, iTunes will throw 1013 error, ignore it, its perfectly normal when downgrading. At this point, your device will be in Recovery Mode with your desired version of iOS fully installed.

Step 5: You should see a screen like this (recovery mode loop). Simply open TinyUmbrella to kick your device out of recovery mode. Congratulations.