Hi, I gave both iOS 4.2.1 and iOS 4.3.3 SHSH Blobs, so after jailbreaking and unlocking my iPhone 3GS (iPad 6.15.00 baseband installed) on iOS 4.3.3, I have decided to downgrade it back to iOS 4.2.1 in order to get better battery performance. However, iTunes is preventing me to restore the custom firmware and it throws iTunes error 1603 every time I try to restore the custom firmware which was created using Sn0wbreeze. Is my iPhone bricked? Please help.
Asked by: Patrick from Little Rock, Arkansas
Step 1: First, you will need to download iREB RC4 and save it on your desktop.
Step 2: Connect your iPhone 4 into your PC via USB cable and launch the downloaded iREB-r4.exe.
Step 3: Then put your iOS device in DFU mode:
- Press Power and Home button at the same time for 10 seconds
- Release the Power after 10 seconds but continue holding the Home button
Step 4: iREB will soon start injecting the Limera1n exploit in the iBoot.
Step 5: Once completed, iREB will inform you that your iPhone is in Pwned DFU mode.
Step 6: Then wait for at least 10 seconds or so and launch iTunes.
Step 7: Once iTunes is opened, select your device at the left side panel. Make sure that you are pressing SHIFT while clicking on the Restore button and browse for the custom iOS 4.3.3 IPSW file and hit OK to commence the restoration process. If you have encountered error 16xx again, immediately disconnect your iPhone and perform the entire process again.
That’s it. You can now restore the custom iOS 4.2.1 on your device without getting 16xx error.