Sarah Jacobson 
The idea is simple, but getting to a point where you have the required files to downgrade iOS may not be as easy as one would hope. This article will show how to get those files and downgrade iOS up until the 5.0.1 untethered jailbreak was released.
To be able to downgrade iOS, you will need SHSH blobs for the version of iOS you are downgrading to. For example, if I am downgrading from iOS 6 to iOS 5.1.1, then I would need the SHSH blobs that are applicable to that downgrade path.
how to downgrade ios 9.3.5 to 9.3.3
There are multiple different options when it comes to SHSH saving for iOS. The most common method is using TinyUmbrella. Other methods include using a tool built into redsn0w, or creating an offline computer and running a back-up of your device with iTunes and then restoring the backup onto a different firmware version. These other methods are not covered in this article.
After downgrading to the version of iOS you would like to jailbreak, you can go ahead and restore your SHSH blobs with TinyUmbrella in order to have them saved in Cydia for future use. The next section will describe how to downgrade iOS up until the 5.0.
What is downgrading iOS and why would you want to do it?
Downgrading iOS is the act of downgrading your current version of iOS to another lower version. This can be done by having SHSH blobs for that version. An example would be downgrading from iOS 7 to iOS 6, or even downgrading any firmware you are currently running on back to 5.1.1 (if possible).
SHSH blobs, also known as ‘Signed Firmware’ or ‘ECID SHSH’, stand for Secure Hash Algorithm. These files are unique signatures associated with your device that Apple uses to verify the firmware currently installed on your iPhone.
How to downgrade iOS – the steps you need to take
1.) First thing you need to do is go ahead and get your hands on the firmware that you want to downgrade to. You can download it freely from our downloads page: http://getios.com/downloads/.
2.) Once you have downloaded and installed iTunes, plug in your device and select ‘Restore iPhone’ (not ‘Update’). iTunes will prompt you to select which firmware file you would like to restore your device with. Select the iOS version that you would like to downgrade to and click continue.
3.) After iTunes has finished restoring your device, go ahead and open up TinyUmbrella (you may need to run it as an administrator). It should display a device ID and ECID. You will need the ECID later on so make sure not to close down TinyUmbrella until you have it written down somewhere.
The benefits of downgrading iOS.
There are several benefits to downgrading iOS. The main reason people downgrade is so they can jailbreak their device on the firmware they desire. A popular example of this was with iOS 6 where you couldn’t jailbreak your device until Apple released iOS 6.1.3, which meant you essentially had no choice but to upgrade if you wanted to jailbreak. With Apple closing down the signing of older firmware versions, this isn’t really an option anymore. However, it is still something that people do for various reasons other than jailbreaking.
Conclusion
Downgrading iOS is something that is possible, but not always recommended. If you do decide to go ahead and downgrade your device, make sure you download the correct firmware file for the version of iOS you want to downgrade back to. Having SHSH blobs saved for your device will ensure that you can always downgrade again should something unexpected happen with the new iOS version. It is also worth noting that with Apple closing down the signing of older firmware versions, this isn’t really an option anymore.
About Author
