How to downgrade iOS 6 on iOS 5.1.1
Earlier this week, Apple released the iOS 6 beta 1 update for iPhone 4S, 4, 3GS, iPad 2, iPad 3 and iPod touch 4G. Anyone can test a new mobile platform using our iOS 6 installation instructions using UDID and even without a developer account. Now it's time to talk about how you can make a downgrade - roll back the iOS 6 operating system on iOS 5.1.1.
Note : iOS 6.0 downgrade on iOS 5.1.1 is possible even without SHSH blobs certificates from this version of the OS, but only for an iPhone with A4 chips.
How to downgrade from iOS 6 to 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 file for your iPhone or iPod touch model
Step 3: Backup the contents of your mobile device through iTunes or iCloud.
Step 4: Run Redsn0w and connect the device to the computer via USB. Put your iOS 6 device into DFU mode ( To do this, hold the lock button for 3 seconds. Without releasing the lock button, press the Home button for 10 seconds. Hold the Home button and release the lock button. Continue to 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 point to the Redsn0w iOS 5.1.1 firmware file that you downloaded in step 2.
Step 7A: If you saved SHSH locally, click the Local button and point the Redsn0w digital certificate .plist file for your device. Skip Step 7b.
Step 7B: If the certificate is stored in Cydia, click the Cydia button, after which the program will create a new IPSW file with the attached certificate. You will use this file for recovery via iTunes.
Step 8: In RedSn0w, go back two pages and click Pwned DFU. This feature will help put the device into Pwned DFU mode to install the firmware. Without it, the error 1600 appears in iTunes.
Step 9: Open iTunes, which informs you that your iGadget is in recovery mode. Hold down the Option (Alt) button on your Mac or Shift on Windows and 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 for the operation to complete.
Step 11: Upon completion, an error (-1) may appear in iTunes. In this case, open RedSn0w and click Extras -> Recovery fix. Put the gadget into DFU mode.
Step 10: That's all, congratulations, you did 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 until the Reciovery Mode is displayed on the screen, and feel free to follow the instructions for entering into the DFU without paying attention to the screen. I got 3 attempts