With Bluefreeze you can easily downgrade your iOS 5.0.1 (tethered) to any iOS firmware even if you don’t have saved SHSH blobs via TinyUmbrella or iFaith – This is what both Private Dev Team and The iPhone Wiki claims. The Bluefreeze run on top of iFaith and modifies iH8sn0w’s iFaith SHSH bundles to downgrade iOS 5.0.1 to iOS 5.0, 4.3.5, 4.3, 4.2.1, and 4.1. Here’s the BlueFreeze video guide followed by text guide.
Note: With this method you can install a firmware for which you don’t have SHSH saved for some tests, for instance, if you’re an iOS developer and need to carry out testing on a specific version.
How to Tethered downgrade iOS 5.0.1 to 5.0 using Bluebreeze
Step 1: Download Bluefreeze and iFaith
Step 2: Make sure your device is running iOS 5.0.1 else you’ll get error 37 in iTunes when restoring, and is impossible to fix that. Once you are on iOS 5.0.1 open up iFaith
Click okay, then click dump SHSH blobs
Enter DFU mode, and then wait…
Step 3: Once you have saved your iOS 5.0.1 SHSH blobs via iFaith, launch Bluefreeze.
Click the blue arrow button (at bottom right) and choose blueJay
Click the blue arrow and then click on the button on screen. Find your iOS 5.0.1 SHSH blobs
Select your firmware, and then select your iOS device
Click on the text “Pwn My iFaith SHSH Blob!”. And it’ll pwn it. You will find your new pwned SHSH blob on your desktop.
Step 4: Re-Open iFaith and this time click on Build *signed* IPSW w/Blobs. Then browse for the Pwned blobs.
Browse, or download your iOS 5.0 ipsw file, then click build
Once it’s finished building it will allow you to go into pwned DFU mode. Do so.
Step 5: Once you’re in Pwned DFU mode open up iTunes. Click shift+restore, browse to the IPSW that iFaith made, and wait for your device to be restored.
Step 6: After the restore your device will not boot up, this is completely normal, open up Bluefreeze again. This time choose bootfreeze option.
After you click the blue arrow Bluefreeze will take a moment and gather a few files (also it’ll ask you to browse for a firmware, just use the original firmware, for example if you restored to iOS 4.3.5 then the not pwned iOS 4.3.5 firmware, same for iOS 5.0), then you will be prompted to this window
When your ready click on ready, and it’ll take you through the instructions on how to put your device into DFU mode (although you should already be in DFU mode). Once your in DFU mode Bluefreeze will recognize it and it’ll boot up your device.
Once your device boots up you can close Bluefreeze, and enjoy your device! (Remember you have to use bootfreeze every time you want to turn your device back on).
Try the Bluefreeze downgrade utility and share the results if it works or not. Sound off in comments, we will try to get in touch with the developers of Private Dev Team for assistance.
Credit: Private Dev Team, The iPhone Wiki