If for some reason you ever need to downgrade your firmware, here's how.
There are a few prerequisites for this process:
- If you have an iPhone 3GS, iPhone 4, iPod touch 3G, 4G, or an iPad, you need to have saved your SHSHs to downgrade to any firmware.
- If you have an iPhone 3G or an iPod touch 2G, you can restore to any firmware between 2.0 and 3.1.3 without an SHSH, but to restore to 4.0 or beyond, you must have the SHSH for that firmware
So, what is an SHSH?
SHSHs are pieces of information that iTunes receives and checks when you are restoring. This occurs when iTunes says “Verifying Restore with Apple”. Since the iPhone 3GS, the SHSH check has been written into the hardware, hence the ability for iPhone 3G and iPod touch 2G to downgrade to anything between 2.0 and 3.1.3. However, since 4.0, Apple has begun placing a software check into the firmware files, hence you need the SHSH for any firmware after 4.0.
So how do I save these “SHSHs”?
Nota Bene (take note), you can only save the most recent firmware’s SHSH, regardless of what firmware you are currently on. If you are on 4.0 and you press “save my SHSH” you will only save the 4.2.1 SHSH, as it is the most recent.
It is very simple to save an SHSH, and you can do it in a couple of ways. You will probably have noticed Cydia asking to “make your life easier” when you first jailbroke your iDevice. If you selected “yes," your SHSHs have been getting saved since you pressed it, you can see which ones you have saved at the top of the home page in Cydia, the green text which I have underlined in red.
You can restore to any firmware you see there, for example, I can restore to any firmware between 4.0.2 and 4.2.1, because I have those SHSHs saved. If you see those numbers there, you can leave it at that, but I also like to have a copy of my SHSHs saved on my computer. To do this, you will need the other way I mentioned. Please note, your Cydia home page is cached, and it may take up to 3 weeks after a firmware’s release for its SHSH to appear.
TinyUmbrella is a program for your computer that allows you to save your SHSHs to Cydia’s server, but also to your local computer. It is very easy to use and free, so you have no excuse not to save your SHSH. You can get it from our download center here.
Once you have downloaded TinyUmbrella, open it up, connect your device, and press “Save SHSHs”. It really is that simple.
Now that you have your SHSH saved, it’s time to learn how to downgrade. This is simpler than it sounds.
Downgrading iDevice firmware
To do this, you will need the SHSH of the firmware saved that you are trying to downgrade to, and the firmware file (.ipsw file), which you can get from out download center here.
Now that you have the firmware file, open TinyUmbrella again and click “Start TSS server”. You have to let TinyUmbrella through your firewall for it to work (there is no need to do this on a Mac unless you specifically turned it on), but it is definitely safe. Thousands of people, including myself and several other writers from AppAdvice, have been using it for years.
After you click it, you will see this:
and if you had iTunes open you will notice it closed itself. This is normal and part of the process.
Okay, take a deep breath, we’re nearly there. Once the TSS server is running, open up iTunes again. Make sure you remember where you saved your firmware file because you’ll need it now.
Now, while holding the Shift key (Windows) or the Option key (Mac), click on the restore button in iTunes. If you did it correctly, you will see a dialogue like this one asking you to select the firmware file you wish to restore to. Select the one you want to downgrade to.
Now, all you have to do is wait and let iTunes restore your iDevice to the firmware you selected. At the end of the process, you will get an error. This is 100% normal and happens every time. To fix this error, without unplugging your iDevice, click on the “kick out of recovery” button in TinyUmbrella.
And that’s it! Pat yourself on the back; you’ve just downgraded your iDevice’s firmware.