Downgrade iPhone 4 firmware
Updated: October 23, 2010If you've read my tutorial on what an ECID SHSH is and how you go about saving it, then you probably want to know how you use that SHSH to restore to firmware that Apple doesn't want you to. This tutorial can be used for any iPhone, and for any firmware as long as you have the SHSH on file for the firmware that you want to restore to. I'll be using an iPhone 4, on 4.1 firmware and I'll restore back to 4.0.1 firmware.
Step 1.
Launch TinyUmbrella (you can download it here) and connect your iPhone. Click on your iPhone in the Connected Devices section and it will display which firmwares you can restore to. In this case 4.0.1 is listed and it is what I'll restore with. This program is updated frequently. So I am hosting the exact same version I am writing about (4.1.12) as I don't have the time to update this tutorial all the time. You can download version 4.1.12 here.
Click the Log tab, then the Start TSS Server button. If you have iTunes open this will close it. Note in the second picture in the Server Console window it states that TSS is accepting connections.
Launch iTunes.
Option click the Restore button and navigate to the firmware you want to restore to. Select it and click Choose.
Click Restore.
Various messages will appear in iTunes while the restore process continues.
You'll see a status bar on the iPhone while it restores.
Click OK when you see this error message.
Click OK at this message.
You'll see the recovery mode graphic on the iPhone.
Go to the Recovery Devices section and select your iPhone then click the Exit Recovery buton (it's also available by right clicking your iPhone). You can then click the Stop TSS Server button and close TinyUmbrella once the iPhone has booted up.
My iPhone is now activated.
Set the iPhone up as new to avoid problems.
iTunes will confirm the iPhone is back on 4.0.1 firmware again. You're finished. Don't forget to jailbreak and unlock again if you need to.
