Comment 3 for bug 1767091

Thank you for reporting this issue.

The shim-signed package, on upgrade, needs to prompt you in order to make changes to the MokManager configuration in your firmware. These prompts are done over debconf. 'exit status 30' is an indicator that something has failed in the debconf.

Looking at the code, it appears there is a bug in the handling of the 'back' button on the "enable secureboot" prompt that would cause this error.

We will look into fixing this code. In the meantime, if you were shown this prompt it means you will need to complete the reconfiguration of your firmware; I recommend that you run 'sudo dpkg --configure -a' to complete this process.