Removing signed kernel installs unsigned one due to dependencies

[Bijo Alex Thomas]

Dell XPS 15 9570. Dual boot with Windows 10. Linux was on 18.04 when attempting to upgrade to 20.04. Had previously installed kernel 4.15-0-177 which was rolled back to working kernel 4.15-0-175 due to issues already reported in Bug #1973482. Due to rollback, there was an unsigned image of kernel 4.15-0-177 in the machine, which caused the upgrade 20.04 to fail with following error. Ubuntu upgrade attempted while logged into kernel 4.15-0-175.

package grub-efi-amd64-signed 1.167.2+2.04-1ubuntu44.2 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: grub-efi-amd64-signed 1.167.2+2.04-1ubuntu44.2
ProcVersionSignature: Ubuntu 5.4.0-110.124-generic 5.4.181
Uname: Linux 5.4.0-110-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.24
Architecture: amd64
CasperMD5CheckResult: skip
Date: Sat May 21 12:24:34 2022
ErrorMessage: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2018-09-23 (1336 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
Python3Details: /usr/bin/python3.8, Python 3.8.10, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.8
SourcePackage: grub2-signed
Title: package grub-efi-amd64-signed 1.167.2+2.04-1ubuntu44.2 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to focal on 2022-05-21 (0 days ago)

[Julian Andres Klode (juliank)]

Thank your for your bug report. This seems to be the result of local misconfiguration, installing an unsigned kernel, and the script does exactly what it was supposed to do.

If you need help with your system, consider using askubuntu, ubuntu-users mailing list, the #ubuntu IRC channel on libera, or other user support channels.

[Bijo Alex Thomas (bijoalex)]

Agree with the comment and this particular update process is likely acting as expected since an unsigned kernel was found. However, just to set the context right - I didn't install the unsigned kernel. I rolled back kernel 4.15-0-177 to work around Bug #1973482, using apt remove and it automatically installed the unsigned version instead.

[Julian Andres Klode (juliank)]

You didn't remove all the 177 packages, the headers package or so pulls in a kernel and then apt switches to the unsigned one.

I'm going to reassign this to Linux, as we should ensure that doesn't happen by not allowing unsigned to satisfy those dependencies.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.