Most jailbreakers remember a useful tool called TinyUmbrella. This was a utility that allowed us to save our SHSH blobs whenever we updated our iOS firmware so that, should the need arise, we could downgrade back to a jailbreakable version. Apple only signs older versions of the iOS firmware for a couple of weeks after releasing an update and, because iOS 9.3.3 is no longer being signed, we cannot downgrade back to it and install PPHelper jailbreak. Right now, we are on iOS 9.3.5 and anyone who has updated is now stuck without a jailbreak.
Image : Prometheus Can Downgrade iOS 9.3.5 to iOS 9.3.2
Good news may be in the offing with a video uploaded by iOS developer and hacker, @tihmstar [Twitter]. He is demonstrating his partially completed tool, called Prometheus, which could take the place of TinyUmbrella [ext link]. The video show Prometheus being used to successfully Downgrade iOS 9.3.5 to iOS 9.3.2 [ext link] on an iPhone 5s, good news indeed because this is the first time we have ever seen a tool of this nature for 64-bit iOS devices.
Video : Prometheus Can Downgrade iOS 9.3.5 to iOS 9.3.2
While we don’t have a great deal of solid information to hand, we do know that, according to the developer, Prometheus will use APTickets and not SHSH blobs. The APTicket is a more up to date form of the SHSH blob but, like TinyUmbrella, you have to save them every time you update if you want to use them for downgrading. There will also be other conditions attached to Prometheus but the developer has not worked out what they are going to be yet.
Prometheus Download :
We can’t give you a date of release; Prometheus is still firmly in the development stages and, according to @tihmstar, is a very complicated tool that nobody will know how to use. If and when it is released, it will need to come with comprehensive guidance on how to use it and what the requirements for use are. However, if this is a legitimate tool and it does end up being released publicly, it will be hailed as a great success, not just by jailbreakers the world over but by those with the 64-bit devices who couldn’t have used TinyUmbrella.
Image : Prometheus ver 1.0 Concept
At this stage, we can only tell you not to pin your hopes on this and, if you are sporting the PPHelper jailbreak on your iOS device, do not update and risk losing it. If you update beyond iOS 9.3.3, you cannot downgrade and you will be left waiting for a new iOS 10 jailbreak, not likely to be released now until sometime after iOS 10. We would urge you to download Cydia Eraser [ext link] though; this will allow you to restore your iOS device in the event of a problem, without updating to the latest iOS firmware.