How to make Downgrade iOS 6 on iOS 5.1.1
Earlier this week Apple released an update iOS 6 beta 1 for iPhone 4S, 4, 3GS, iPad 2, iPad 3 and iPod touch 4G. Anyone can test a new mobile platform using our installation instructions for iOS 6 using UDID and even without a developer account. Now it's time to talk about how you can make a downgrade - roll back the operating system iOS 6 on iOS 5.1.1.
Note : Downgrade iOS 6 on iOS 5.1.1 is possible even without SHSH blobs from this version of the OS but only for iPhone with A4 chips.
How to make downgrade with iOS 6 on iOS 5.1.1 for devices on A4
Step 1: Download RedSn0w 0.9.14b2 for Windows and Mac OS X.
Step 2: Download the iOS 5.1.1 firmware for your iPhone or iPod touch
Step 3: Back up the contents of your mobile device through iTunes or iCloud.
Step 4: Start Redsn0w and connect the device to the computer via USB. Place the device on iOS 6 in DFU mode ( Hold the lock button for 3 seconds without releasing the lock button, press the Home button for 10 seconds.) Hold the Home button, release the lock button, and hold the button for 30 seconds ).
Step 5: Click the Extras button in RedSn0w, then SHSH blobs, and then Stitch.
Step 6: You will see three options: IPSW, Local and Cydia. Click on the IPSW button and specify the Redsn0w firmware iOS 5.1.1 downloaded in step 2.
Step 7A: If you saved SHSH locally, click the Local button and specify the Redsn0w .plist file with a digital certificate for your device. Skip Step 7B.
Step 7B: If the certificate is saved in Cydia, click the Cydia button, after which the program will create a new IPSW file with a certificate attached. This file will be used for recovery through iTunes.
Step 8: In RedSn0w, go back two pages and click Pwned DFU. This function will help you put the device into Pwned DFU mode to install the firmware. Without it, iTunes will show error 1600.
Step 9: Open iTunes, which informs you that your iGadget is in recovery mode. While holding down the Option (Alt) button on the Mac or Shift on Windows, click the Restore button. Select the file created in Redsn0w.
Step 10: At this point, iTunes will automatically install iOS 5.1.1 firmware on the gadget. Wait until the operation is complete.
Step 11: After finishing iTunes, you may receive an error (-1). In this case, open RedSn0w and click Extras -> Recovery fix. Put the gadget in DFU mode.
Step 10: That's all, congratulations, you made downgrade iOS 6 on iOS 5.1.1. Now you can do JailBreak !
Note : In Step 11, there may be a problem entering DFU mode. Connect the phone to the computer, wait for the Reciovery Mode to be displayed on the screen, and safely follow the instructions for entering the DFU without paying attention to the screen. I did it with 3 attempts