Update: tihmstar has stated that the tool is working perfectly, and that he has used it successfully multiple times today. However, some users have been encountering a TSS server error when using the tool nonetheless.

Hot on the heels of Prometheus’ release at the 33c3 convention two days ago, tihmstar’s tool for upgrading and downgrading to unsigned iOS firmwares seems already to have hit a snag. Following some changes to Apple’s TSS servers today, the nature of which are yet to be investigated, the tool has been rendered non-functional at the present time.

The first misconception to clear up, which has been repeated in many places, is that Apple has completely taken its TSS servers offline. That is not the case; the servers are clearly still up, as can be proven by attempting to restore or upgrade a device through iTunes. If the TSS servers truly were down, no iTunes restores would be able to complete.

Having said that, some changes to the servers do seem to have been made, as attempting to connect to them returns an error, and Prometheus is unable to proceed at the present time. This is due to the fact that it relies on currently signed SEP and baseband sections during its restore process. Even though it circumvents signing for the rest of the process by using your saved blobs, an inability to get the TSS server to approve the SEP and baseband signing will cause the tool to fail.

A second rumour which has been perpetrated by some is that Apple will temporarily sign all firmwares when the servers come back online. Whilst this is not literally impossible, it is almost certainly false. Firstly, because as already discussed the servers are not totally down, and secondly, because there is no reason to think they would be forced to do so even if they were. This idea seems to be driven more by hope than anything else, and I would not place any amount of reliance in it, especially not in making decisions about upgrading or downgrading your devices.


Tihmstar has not yet commented on what changes have been made by Apple, only stating that they have not shut down the servers. As he is currently attending the 33c3 convention in Hamburg he may not be able to look into the issue for a few days, but I am cautiously optimistic that the issue will be able to be worked around.

At the moment all that can be said is that something has changed server-side which is preventing Prometheus from working as it did before, but whether it is improved verification of signing requests in response to his tool’s release or just coincidental maintenance, can not be known for sure. If some patches have been applied, only tihmstar will be able to clarify if they can be worked around, or if they have rendered his methods fundamentally impossible going forward.

For now, the following common sense practices should apply:

  • Do not try to use Prometheus to restore your device. It will fail and, although unlikely, may force you to upgrade to iOS 10.2.
  • Do not try to restore to any other unsigned firmware based on word-of-mouth promises that they will be signed again; this is foolish.
  • Do not angrily delete your saved blobs in the belief that Prometheus will never work again, or do anything else rash like upgrade to iOS 10.2. Be patient and see if the tool can be made to work again.

One final piece of Prometheus news, which is not related to the TSS server trouble but is still relevant, is that tihmstar has identified a problem with iPhone 7(+) .shsh2 blobs saved with TSSChecker. Again, do not panic and do not delete the blobs if you have them saved. Whilst he claims the blobs will not be able to be used with his Prometheus tool, he says they may still be usable with a different technique. He has also mentioned that he can fix TSSChecker so that it saves iPhone 7(+) blobs correctly from now on, so look out for that update.

Have you personally encountered a failed Prometheus restore due to the TSS servers refusing requests? Did you have iPhone 7(+) blobs saved? Say your piece below, and in the meantime, be patient and wait for developments from tihmstar.

  • I got my 7+ blobs saved for 10.1.1 and 10.2. Hopefully il be able to use them with a much easier tool.

    • Joaquim Barbosa

      tihmstar has said that the blobs may still be usable with a different tool, just not with prometheus as it currently is. He has also said that he can fix TSSChecker to work with iP7(+), so that in future blobs saved with it will work with Prometheus. We will have to wait for that update though…

  • Melma

    Wow that was faster than my Cable modem

  • Scott Curry



  • Diego Milano

    The more I read about Prometheus, the jailbreak process which is still in beta, the new Cydia app released which is also still in beta, the more I think iOS 9.3.3 will be the last stable jailbreak in a long while. I’m glad to be running it. Sorry iOS 10, but… we may not see each other after all.

  • (JailbreakQA) King Shoot

    Do the changes to the server render iFaith-based restores useless or are those still okay?

    • Joaquim Barbosa

      Which restores are you referring to? Which iOS versions?

      • Bugs Bunnay

        he’s probably referring to the older ios 6 and below

      • (JailbreakQA) King Shoot

        Restores made with custom iFaith IPSW. The ones where you stitch SHSH to an IPSW and restore to an older firmware.

        And I’m referring to iOS 6 and older of course, since these types of restores do not work with iOS 7 or newer.

      • Joaquim Barbosa

        They are totally fine, no worries!

  • Mark S

    I figured they would shut this down if possible on their end. Apple doesn’t just sit around when it comes to the iphone. That’s their bread and butter device.

    • Joaquim Barbosa

      Seems the process is back working again now though, who knows what it was all about…

  • Josh

    I was originally getting the same issue but I realised I was using the plist file instead of the .bbfw file for the baseband. Once I corrected that it worked fine. Basically double check and make sure you’re using the correct files.

  • Tyson Edwards

    I saved my 10.1.1 and 10.2 blobs for my iPhone 6S Plus, too bad I didn’t save my shah2 when they still signed 9.3.2 that I’m currently on.