You Will Soon Be Able to Upgrade / Downgrade Your iPhone, iPad to Unsigned iOS Firmware
Great news for jailbreak users as you will soon be able to upgrade or downgrade your device to any iOS firmware that is unsigned by Apple.
Prometheus (Not the Movie) Will Allows You to Upgrade or Downgrade Your iPhone, iPad, iPod touch to Unsigned Firmware
A new tool called Prometheus, announced by tihmstar, will allow users to effortlessly downgrade or upgrade their device firmware without worrying about it being signed or not. But this magic will be available for 64-bit devices only. The support for 32-bit devices will arrive, eventually, but at a later point in time.
There is a huge prerequisite before this can happen though: you must have SHSH blobs saved for the particular firmware you are downgrading or upgrading to. But not just regular blobs will do; they should be saved in the new .shsh2 format otherwise nothing will move a muscle. You can do this using tihmstar's new tool called tsschecker (GitHub download link).
Another prerequisite is that you should be sitting on a jailbroken firmware in order to jump onto the next one. For example, if you are currently on iOS 10.1.1, and want to say, downgrade to iOS 9.3.3, then iOS 10.1.1 should be jailbroken. And of course, blobs for iOS 9.3.3 should be saved as well, that too in .shsh2 format. All of this may sound a little too complicated, but for those who live the jailbreak life will find it to be a walk in the park.
tihmstar said the tool will arrive on New Year's Eve, so you may you want to mark your calendars beforehand. Also, here's a video explaining how Prometheus will work.
If you know your way around jailbroken iOS devices, then you should go ahead and save your blobs right away. If you haven't though, then you might want to downgrade your device to iOS 10.1.1 as well as a potential jailbreak is on its way:
At the time of writing, Apple is currently signing iOS 10.1.1, a firmware with certain vulnerabilities that can be exploited to jailbreak a device. It's only a matter of time Apple closes the signing window and puts everything to rest. So please, if you are eager to jailbreak your device, then you might want to take the time out to restore your smartphone or tablet to iOS 10.1.1 using iTunes.
As soon as we have further news regarding iOS 10.1.1 jailbreak, we will inform our readers about it. Till then, sit tight, and keep on checking this space for more updates.