FIX Cydia iOS 11.4.1 – 12.4/ fix sub-process /usr/libexec/cydia/cydo returned an error code (255)


Since the Unc0ver 4.0 update, a lot of Unc0ver (mainly devices running iOS 11.4.1 – 12.4) users who upgraded to the latest version of Unc0ver have been facing sub-process /usr/libexec/cydia/cydo returned an error code (255) which renders Cydia useless considering the fact that you can’t use/install any tweaks.

The main reason you’re facing the issue is cuz the Unc0ver version 4.0 isn’t compatible to jailbreak iOS 11.4.1 – 12.4 devices, so you need to get the previous version of Unc0ver to fix this issue.

Today we at are going to be telling you how to fix this error (255).


Firstly, you’re going to need 2 apps (Documents and AppCake) that will help you install the Unc0ver 3.8 IPA.

Follow the steps below:

After downloading both apps, Open the Documents app and follow the steps below.

  • After the download is done click on the IPA file
  • Click on “Open in another app” (make sure you have AppcCake downloaded on your phone)
  • Copy to AppCake
  • Goto “Downloads” Tab on AppCake and install Unc0ver.

Once the installation is done, you can go ahead and Jailbreak your device and you shouldn’t be getting any more error when installing a tweak.

Hope this article was helpful. 🙂

You can watch a video tutorial below:



Publisher at LOG.NG

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  1. Grazie a funzionato però dopo due giorni non si aprono unc0ver e app cake mi dice applicazione non verificata e non si po verificare. Qualcosa stabile per unc0ver 3.8.0 e per app cake non c’è ? Grazie.

    English Translation:

    Thanks to worked, however, after two days unc0ver does not open and app cake tells me an unverified application and it cannot be verified. Something stable for unc0ver 3.8.0 and for app cake is not there? Thank you.

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