One of the more common questions we’ve been getting here at iDB since the release of the Yalu jailbreak for iOS 10 is when AppSync Unified, from Karen Tsai (angelXwind), would be getting an update to make it compatible with the new jailbreak.

As you may be aware, many people got themselves into a respring loop of some description by installing AppSync soon after the Yalu jailbreaks came out. That should now have been fixed with this new beta version of AppSync Unified, available on Karen’s Cydia repository.

What is AppSync?

AppSync is a powerful tweak which allows the installation of unsigned .ipa files (iOS applications) on your jailbroken device. Whilst it is true that this functionality is often used for nefarious purposes, the central intent of AppSync is valid and useful. It allows on-device installation of legal apps for those without a Mac or Xcode, as well as the distribution of legal but unsigned apps by those who cannot make it onto the App Store, for example, emulator applications.

However, it can be (and is) unfortunately also used for the installation of paid apps for free. For more information on the real purpose of AppSync and the reasoning behind its legitimate uses, you can read Tsai’s post on the subject.

I personally use it to install emulators such as GBA4iOS, as well as older versions of applications for legacy devices, which are no longer available from the App Store.

AppSync in beta for iOS 10

The new build number is 6.0~b1, and the changelog consists of one major item to prevent crashes on, and bring compatibility to, iOS 10:

Return the public “Apple iPhone OS Application Signing” intermediate certificate instead of “kSecMagicBytes” on iOS 10 to avoid a Security.framework crash — thanks JulioVerne!

Tsai goes into more detail as to what caused the problem in her announcement post, but the basic premise is that AppSync gives fake data to the installd process in order to sign your unsigned apps, however, on iOS 10 this causes the Security.framework to crash installd. Then, when Cydia installs a package and runs uicache it calls on installd, which crashes, leaving your SpringBoard in a half-way, broken state: a respring loop.

In fixing this problem, Tsai was helped out by developer and software-cracker JulioVerne. Much had been wildly speculated about whether the two were in ‘competition’, after Tsai initially advised against installing his fixed-up version. However, this turned out to be incorrect, as explained by Tsai in the announcement post I linked above.

To summarise: the two have worked together to bring this solution, with JulioVerne providing his source code for the fix. This allowed Tsai to check its legality (it uses an Apple certificate), and restore iOS 5 & 6 support, which the initial fix unwittingly broke. She has now been able to release an official version of the package, which fixes all these issues and can prevent version fragmentation, by being offered on her official repo. She credits JulioVerne with the fix, and thanks him for his help.

If you want to try out the beta of AppSync Unified, it can be found on Karen Tsai’s Pineapple repo:

Please ensure that the only version you install is the one from this repository. Installing an older version could leave you in the respring loop, and many repositories offer old versions of this package. Install AppSync Unified 6.0~b1 only from Karen’s Pineapple repo.

Are you excited to have AppSync Unified on iOS 10? Have you tried it out yet?

  • Julio Hernandez

    So could this be used as a solution to the Yalu app having to be signed every 7 days?

    • Steve Harold

      No appsync only works in jaikbroken state.

      Well actually if you were jailbroken and the certificate expired you could still use it, but that is useless.

      • Julio Hernandez

        Ah okay thank you for letting me know. And yeah it would be useless since my 6s+ still suffers from that 20-30% battery bug and randomly shutting off. 🙁

      • Chris Ryan

        my 6 has that problem too, tho it just started there a fix for this?

      • Julio Hernandez

        So far not that I’m aware of except for carrying a battery bank with you. Even Apple’s forums have been filled up with this issue and it’s most commonly known as the “30% battery bug”. For me it started since iOS 9 and has persisted till now.

      • G0DLeᎦᎦ

        I noticed my iPhone 6s sometimes shuts off at 20%-10% battery. This only happens when I’m not in LowPowerMode though.

  • Nathan Peterson

    Bummer. Can’t install for 10.1.1

    • Dom Sad

      Why.? Works fine on my 10.1.1 7+

      • Garry

        Hows the ip7plus jailbreak holding up im on 10.1.1 and still havent jailbroken it any precautions i should take??

      • Dom Sad

        It’s very unstable and when installing new tweaks sometimes phone will reboot and also can’t do resorting in Cydia as it will reboot the phone as well.

      • Garry

        Ok so my best bet is to wait for luca to comeup with a new beta for the jailbreak for the ip7

      • Nathan Peterson

        It is very unstable although installing a substrate fix for 10.1.1 has helped slightly.

      • Garry

        Dont you think this is just a carelessness from lucas part why not just come out with a update so everyone can enjoy rather than only old devices supporting the jailbreak i wish pangu or taig were here

      • Zohar

        The guy doesn’t owe you anything. Want a more stable jailbreak on your specific configuration? Please do it yourself.

      • Garry

        If we peple could we definitely would have done it try to come up with a better argument

      • Zohar

        My argument is definitively valid : you can’t do it and you don’t pay him to do it, so shut up and wait instead of bitching him.

      • Nathan Peterson

        When I try to install it, it say, “Depends IOS Firmware >=10.0”

      • Nathan Peterson

        I fixed my issue. My phone thought I was on 9.3.4. This is what I did: Download Filza Open Var/lib/dkpg/”status” open in text editor. Scroll down until you hit Package:Firmware and change the version to 10.1.1/10.2 whichever you are on. Mine was on 9.3.4 for some reason. Respring and all should be good.

  • Alok Jha

    Hello guys.
    It works gr8. No restart loops at all. Easy and quick installation.

  • MelMa D Teach

    Its working great

    • Hakuna

      Maybe try Repoleak but don’t know too much about it, research it first

      • MelMa D Teach

        Thank you

  • 7000rpm

    Ssh client?

  • ishinne_Diabetes

    i hope you ALL know, that this Tweak is completely illegal.

    • stylesbeyond

      i hope you know you have no clue what you’re talking about

      • ishinne_Diabetes

        Of course i have. Read the discription about the tweak. “Allows you toninstalled unsigned apps”. That means, that u can install hacked/cracked Apps as well

      • Firedomain

        It means you can, but that doesn’t make it illegal. Pirating apps is illegal, but I can use appsync to install games that I’m developing without having to sign them all every time I want to test it. & that’s definitely not illegal.

      • Zohar

        Of course you don’t. A knife could be used to kill someone : would it be illegal to buy one then? Try to think before posting crap.

    • chris chick

      so bloody what…..Freak

  • Diego

    Still waiting jailbreak for my new iPhone 7 that came with iOS 10.2
    Miss my iPhone 6 jailbroken

  • Gabriel Schwartz

    Good news. Now the only missing part is Apple TV 4 JB!

  • Karel Zwaneveld

    AppSync not on her Repo?

  • Karel Zwaneveld

    Where to find Appsync?

    • T Mack

      I have the same issue. Appsync is not appearing on Karens Repo. Anyone know why? I have tried to delete the repo, but it doesnt