In this guide you’ll learn how to downgrade iOS 4.2 to iOS 4.1 / 4.0.1 on iPhone 4, 3GS, 3G and iPod Touch 4G, 3G, 2G. Follow the steps below to downgrade iOS 4.2 to 4.0.1/4.0 firmware on iPhone and iPod Touch.
iOS 4.2 is not jailbreakable ATM. So, if you want to jailbreak iPhone 4, 3GS, 3G or iPod Touch 4G 3G, 2G then you MUST downgrade to iOS 4.1 or 4.0.1 first. iOS 4.1 jailbreak is expected soon.
In this guide we’ll discuss following two methods to downgrade iOS 4.2 iPhone / iPod Touch firmware:
Using TinyUmbrella (Recommended)
By Editing Hosts file
IMPORTANT: iPhone 4, iPhone 3GS, 3G, iPod Touch 4G, iPod Touch 3G, 2G users MUST have SHSH blobs saved for 4.0.1/4.0 firmware in order to downgrade from iOS 4.2.
Method : Using TinyUmbrella
Download TinyUmbrella from the link below:
If you’ve SHSH blobs saved on Saurik’s server via Cydia, download them into your computer first. To do that:
Connect your device, Fire up the TinyUmbrella and Check mark the Advanced Options.
Select your device, firmware (the one for which you’ve SHSH saved at Cydia; 4.1, 4.0.1 or older) and Cydia as Location.
Hit the save My SHSH button. that’s it.
Step 1 – DFU Mode
Put your iPhone into DFU Mode (How to: enter DFU Mode)
Step 2 – Start TSS Server
Run the TinyUmbrella
Hit the Display SHSH button to confirm that downloaded SHSH blobs has been cached by TinyUmbrella for 4.1, 4.0.1 or older. (If you already have them in your PC, drag and drop the SHSH blobs in the TinyUmbrella window then hit the display SHSH blobs button to confirm).
Then hit the Start TSS Server button.
Step 3 – Restoring The Firmware
Now Open the iTunes.
Hold down the Shift (Windows)/Alt (Mac) key and hit the Restore button.
Select the downloaded firmware (iOS 4.1, iOS 4.0.1 or older) and let the restore process complete.
iTunes will bring up error 1015, 1013 or 1011 message. Don’t worry, it’s normal. You’ve successfully downgraded your iPhone/iPod Touch firmware.
Step 4 – Getting Out Of Recovery
Now in order to get out of recovery mode, hit the “Kick Device Out of Recovery” button on TinyUmbrella right below the Start TSS Server button or you can also use RecBoot That’s it!