package grub-efi-amd64-signed 1.128+2.04-1ubuntu12 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1

[Chiranjib Bhattacharya]

I have ubuntu 16.04 customised version installed in my computer.

ProblemType: Package
DistroRelease: Ubuntu 19.10
Package: grub-efi-amd64-signed 1.128+2.04-1ubuntu12
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: Mon Nov 25 17:39:00 2019
ErrorMessage: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2018-10-06 (414 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
Python3Details: /usr/bin/python3.7, Python 3.7.5rc1, python3-minimal, 3.7.5-1
PythonDetails: N/A
RelatedPackageVersions:
 dpkg 1.19.7ubuntu2
 apt 1.9.4
SourcePackage: grub2-signed
Title: package grub-efi-amd64-signed 1.128+2.04-1ubuntu12 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)