package grub-pc 2.02-2ubuntu8 failed to install/upgrade: installed grub-pc package post-installation script subprocess returned error exit status 20

[Mr Anthony J Howell]

Upgrading from 17.10 to 18.04. Grub failed to update

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: grub-pc 2.02-2ubuntu8
ProcVersionSignature: Ubuntu 4.15.0-24.26-generic 4.15.18
Uname: Linux 4.15.0-24-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
Date: Sat Jun 16 20:49:36 2018
DuplicateSignature:
 package:grub-pc:2.02-2ubuntu8
 Setting up grub-pc (2.02-2ubuntu8) ...
 dpkg: error processing package grub-pc (--configure):
  installed grub-pc package post-installation script subprocess returned error exit status 20
ErrorMessage: installed grub-pc package post-installation script subprocess returned error exit status 20
InstallationDate: Installed on 2017-04-15 (427 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-24-generic root=UUID=f56e8ba1-a497-468b-b2ac-22a8ca881a5a ro intel_iommu=on iommn=pt rd.driver.pre=vfio-pci
Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-3
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.1
SourcePackage: grub2
Title: package grub-pc 2.02-2ubuntu8 failed to install/upgrade: installed grub-pc package post-installation script subprocess returned error exit status 20
UpgradeStatus: Upgraded to bionic on 2018-06-16 (0 days ago)

[Phillip Susi (psusi)]

Please edit /var/lib/dpkg/info/grub-pc.postinst and change the second line from set -e to set -ex, save it, and run sudo apt-get install -f to retry and post the output.

[Launchpad Janitor (janitor)]

[Expired for grub2 (Ubuntu) because there has been no activity for 60 days.]