package flash-kernel 3.103ubuntu1~20.10.1 failed to install/upgrade: installed flash-kernel package post-installation script subprocess returned error exit status 1

[Sam Leestmans]

processing triggers for flash-kernel (3.103ubuntu1~20.10.1) ...
Can't find /boot/vmlinuz- (see /tmp/flash-kernel-no-kernel-error.log)
dpkg: error processing package flash-kernel (--configure):
 installed flash-kernel package post-installation script subprocess returned err
or exit status 1
Processing triggers for libc-bin (2.32-0ubuntu3) ...
Errors were encountered while processing:
 u-boot-rpi:arm64
 flash-kernel
E: Sub-process /usr/bin/dpkg returned an error code (1

ProblemType: Package
DistroRelease: Ubuntu 20.10
Package: flash-kernel 3.103ubuntu1~20.10.1
Uname: Linux 5.4.73v64 aarch64
ApportVersion: 2.20.11-0ubuntu50.5
Architecture: arm64
CasperMD5CheckResult: skip
Date: Sun Feb 7 21:52:11 2021
ErrorMessage: installed flash-kernel package post-installation script subprocess returned error exit status 1
ImageMediaBuild: 20201022
Python3Details: /usr/bin/python3.8, Python 3.8.6, python3-minimal, 3.8.6-0ubuntu1
PythonDetails: N/A
RebootRequiredPkgs: gnome-shell
RelatedPackageVersions:
 dpkg 1.20.5ubuntu2
 apt 2.1.10ubuntu0.2
SourcePackage: flash-kernel
Title: package flash-kernel 3.103ubuntu1~20.10.1 failed to install/upgrade: installed flash-kernel 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.

[Jaques Viljoen (jaques-viljoen)]

Running on Pi 4 with 4GB RAM
Using external USB HDD and booting via BootBerry to select between Ubuntu and Raspbian.