package grub-efi-amd64-signed 1.128.1+2.04-1ubuntu12.1 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1

[Robert Lee]

Message popped up on reboot.

Errors during software update.

ProblemType: Package
DistroRelease: Ubuntu 19.10
Package: grub-efi-amd64-signed 1.128.1+2.04-1ubuntu12.1
ProcVersionSignature: Ubuntu 5.3.0-23.25-generic 5.3.7
Uname: Linux 5.3.0-23-generic x86_64
ApportVersion: 2.20.11-0ubuntu8.2
Architecture: amd64
Date: Tue Nov 26 19:18:23 2019
ErrorMessage: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2019-05-05 (205 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
Python3Details: /usr/bin/python3.7, Python 3.7.5rc1, python3-minimal, 3.7.5-1
PythonDetails: /usr/bin/python2.7, Python 2.7.17rc1, python-minimal, 2.7.17-1
RelatedPackageVersions:
 dpkg 1.19.7ubuntu2
 apt 1.9.4
SourcePackage: grub2-signed
Title: package grub-efi-amd64-signed 1.128.1+2.04-1ubuntu12.1 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Tim Nolte (tim-nolte)]

I found that this was due to System76 Pop!_OS kernels having gotten installed, which also explains when those were installed why I problems booting them and had to manually boot to the 5.0 signed kernel. Something to be aware of is that the System76 PPA is not just for their DDE but for the entire system.