With the imminent release of iOS 8.4 on Tuesday, it may be a good idea to save iOS 8.3 SHSH blobs using TinyUmbrella, so that you have the option to downgrade to iOS 8.3 even after Apple’s stops signing the iOS 8.3 firmware file.
Before we go into the details on how to save the SHSH blobs, and other details, here is some background about SHSH blobs, and why they’re important.
As you probably know, Apple allows you to restore only to the latest iOS versions to prevent users from downgrading to an older iOS version, which would have made it easier to jailbreak the iOS device.
Apple stops signing the firmware files (by not providing SHSH blobs) for older iOS versions to prevent users from downgrading to the older version. Tools like TinyUmbrella allowed you to save the SHSH blobs while the firmware is still being signed, so you could use it to create (stitch) a pre-signed IPSW file using tools like Redns0w, which could then be used to restore your device with an iOS version that Apple was no longer signing. However, Apple closed the loophole that allowed users to use the SHSH blobs to downgrade to an older version in newer devices (iPhone 4S and later) and also in iOS 7 or later. So you cannot restore to 6.x or higher using SHSH blobs except on iPhone 4, iPhone 3GS, and iPod touch 4G (and iPad 2 to iOS 5.x if you have iOS 4.x and iOS 5.x SHS blobs).
However, SHSH blobs could be relevant again thanks to a new exploit discovered by iH8sn0w, developer of Sn0wbreeze andPosixspwn jailbreak tools, indicating that it may be possible to downgrade to an older iOS version even if Apple was not signing it using SHSH blobs. So for example: if it is not possible to jailbreak iOS 8.4, then you could downgrade to iOS 8.3 even though Apple is not signing iOS 8.3 firmware file, and use TaiG jailbreak tool to jailbreak your device.
How to save SHSH blobs using the new TinyUmbrella beta:
- Download the new TinyUmbrella beta from this link (click on the download link in the right sidebar under Downloads/Links). It is available for both Mac and Windows.
- TinyUmbrella requires Java installed, so download it from this link and install it on your computer.
- Launch TinyUmbrella.
- Now connect your iOS device to the computer. TinyUmbrella should automatically recognize it and begin downloading all of the available SHSH blobs.
You can also check our video tutorial:
That’s it. You’ve successfully downloaded the SHSH blobs for your iOS device. You should see SHSH blobs downloaded for iOS 8.3 in the list.
Answers to Frequently asked questions:
- TinyUmbrella will automatically download the SHSH blobs for firmware files that are currently being signed by Apple.
- You can also fetch SHSH blobs from A7/A8 devices on iOS 8.2 or earlier using TinyUmbrella, check this post for more details.
- The SHSH blobs are saved at the following location: ~/.tu/.shsh. You can check the folder to see if it has been saved.
- Unlike the previous version, all the SHSH blobs are saved in a single file.
- There are three types of SHSH blobs namely: Update (Restore), Erase (Restore) and OTA. We’re assuming they are meant for different types of actions.
- TinyUmbrella keeps a record of the known devices in ~/.tu/.known_devices folder. You can delete the file in that folder if you want to clear the history.
- It is important to note here that you won’t be able to downgrade currently though Semaphore seems quite bullish about the ability of downgrading in the future. We’ll let you know as soon as we get any further updates.
- You can’t use SHSH blobs of another iOS device. SHSH blobs are unique for a device, so it is important to download the SHSH blobs for your device.
Let me know how it goes, and feel free to drop me in a line in the comments if you’ve any other questions.
