package shim-signed 1.40.4+15+1552672080.a4a1fbe-0ubuntu2 failed to install/upgrade: dependency problems - leaving triggers unprocessed

[Morten Efferbach Toft]

This bug started when i tried to install an Opencv package called "opencv2/nonfree/nonfree.hpp" for C++. I tried installing following the package following the steps in the answer in this thread "https://stackoverflow.com/questions/28525810/fatal-error-opencv2-nonfree-nonfree-hpp-no-such-file-or-directory". I have Opencv version 4.2 installed.

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: shim-signed 1.40.4+15+1552672080.a4a1fbe-0ubuntu2
ProcVersionSignature: Ubuntu 5.4.0-48.52-generic 5.4.60
Uname: Linux 5.4.0-48-generic x86_64
.proc.sys.kernel.moksbstate_disabled: Error: [Errno 2] No such file or directory: '/proc/sys/kernel/moksbstate_disabled'
ApportVersion: 2.20.11-0ubuntu27.10
Architecture: amd64
BootEFIContents:
 BOOTX64.CSV
 grub.cfg
 grubx64.efi
 mmx64.efi
 shimx64.efi
CasperMD5CheckResult: skip
Date: Mon Nov 2 16:16:53 2020
ErrorMessage: dependency problems - leaving triggers unprocessed
InstallationDate: Installed on 2020-09-22 (41 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
Python3Details: /usr/bin/python3.8, Python 3.8.5, 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 2.0.2ubuntu0.1
SecureBoot: 6 0 0 0 1
SourcePackage: shim-signed
Title: package shim-signed 1.40.4+15+1552672080.a4a1fbe-0ubuntu2 failed to install/upgrade: dependency problems - leaving triggers unprocessed
UpgradeStatus: No upgrade log present (probably fresh install)

[Steve Langasek (vorlon)]

The error in your log is:

Setting up grub-efi-amd64-signed (1.142.8+2.04-1ubuntu26.6) ...
/boot/vmlinuz-5.8.10 is unsigned.
E: Your kernels are not signed with a key known to your firmware. This system will fail to boot in a Secure Boot environment.
dpkg: error processing package grub-efi-amd64-signed (--configure):
 installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1

This is not a bug in shim-signed, the package deliberately refuses to upgrade informing you that upgrading will render your system unbootable.

/boot/vmlinuz-5.8.10 is not an official Ubuntu kernel, which means that with recent versions of shim which enforce kernel signatures, your system will fail to boot.

You need to either disable SecureBoot in your firmware, or use a signed kernel.