Here is a step-by-step guide which can help you to downgrade your iPhone, iPod Touch or iPad firmware from iOS 4.3 final to iOS 4.2.1/4.1/4.0.1/4.0.2/4.0. Same guide is valid to downgrade your iDevice from iOS 4.3 to iPhone OS 3.1.3/3.1.2. As iOS 4.3 is not available for iPhone 3G and iPod Touch 2G, so all iDevices will be needing SHSH blobs saved for the iOS to which they want to downgrade.
- Download iTunes 10.2.1 from here
- Download iH8sn0w's iREB RC4 tool from here. This will help you to avoid 1600, 1601, 1602, 1603, 1604 and 1015 error. If you are on Mac, use this instead of iREB.
- Download stock or custom IPSW of the firmware to which you want to downgrade
- Download TinyUmbrella for Windows or Mac from here
Download iOS 4.2.1 for iPhone 4/3GS/3G, iPod Touch 4G/3G/2G & iPad
Download iOS 4.1 for iPhone 4/3GS/3G & iPod Touch 4G/3G/2G
Download iOS 4.0 for iPhone 4/3GS/3G & iPod Touch 2G/3G
Download iPhone OS 3.1.3 for iPhone 3GS/3G/2G
Download iPhone OS 3.1.2 for iPhone 3GS/3G/2G
Step to Downgrade iOS 4.3 Final to iOS 4.2.1/4.1/4.0/3.1.3/3.1.2:
- Connect your iPhone, iPod Touch or iPad to your PC or Mac via USB cable.
- Launch TinyUmbrella app and wait while it detects your iDevice.
- Once TinyUmbrella has detected your iDevice, select it from the side-panel and hit the Save SHSH button. TinyUmbrella will download all of your saved SHSHs from Cydia and will save them to your hard-drive
- Once saved, switch to the LOG tab and click on Start TSS Server button. Make sure iTunes is closed at this time.
- Clicking on Save SHSH button will download all of your SHSH blob files from Cydia to your computer's hard drive. Once done, launch iREB and click on the name of your iDevice. Let TinyUmbrella to run in background.
- Put your iDevice into DFU mode using the instructions below:
- Turn off your iPhone completely
- Press and hold the Home+Power button simultaneously for 10 seconds.
- After 10 seconds, release the Power button but keep holding the Home button until iREB detects your iDevice in DFU mode.
TSS Server Started!
TSS Accepting connections...
Stuck in Recovery Mode After Downgrade?
If your iPhone, iPod Touch or iPad is stuck in recovery mode after downgrade, you can try the following tools to kick your iDevice out of recovery mode loop.
- If downgrading to iPhone OS 3.1.3/3.1.2, use RecBoot [Windows | Mac]
- If downgrading to iOS 4.1/4.0, use TinyUmbrella. Follow instructions here.
- If stuck in iOS 4.2.1 recovery mode loop, use special version of TinyUmbrella i-e TinyUmbrella (Fix Recovery) [Windows | Mac]
Tip1: After step 9, open your default browser and type http://gs.apple.com/, it should redirect to Cydia home.
Tip2: If you do not want to use TinyUmbrella, simply add the following line to your Windows or Mac HOSTS file.
Be Sure to Check Out: