package grub-pc 2.04-1ubuntu26.9 failed to install/upgrade: installed grub-pc package post-installation script subprocess returned error exit status 127

[Condescending_fox]

Auto update bug

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: grub-pc 2.04-1ubuntu26.9
ProcVersionSignature: Ubuntu 5.8.0-43.49~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-43-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
CasperMD5CheckResult: skip
Date: Fri Feb 26 06:22:14 2021
ErrorMessage: installed grub-pc package post-installation script subprocess returned error exit status 127
InstallationDate: Installed on 2021-02-11 (14 days ago)
InstallationMedia: Ubuntu 20.04.2 LTS "Focal Fossa" - Release amd64 (20210204)
InvalidGrubScript: /etc/default/grub
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.8.0-43-generic root=UUID=20534a56-5f13-414f-9a24-e86b47782945 ro quiet splash acpi_backlight=vendor vt.handoff=7
Python3Details: /usr/bin/python3.8, Python 3.8.5, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: N/A
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.4
SourcePackage: grub2
Title: package grub-pc 2.04-1ubuntu26.9 failed to install/upgrade: installed grub-pc package post-installation script subprocess returned error exit status 127
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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

[Mate Kukri (mkukri)]

This looks to be a corrupted /etc/default/grub