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

[Konstantin]

I can't update system at all because following fault

Software Updater on Raspberry Pi4:

The installation or removal of a software package failed

ProblemType: Package
DistroRelease: Ubuntu 20.10
Package: flash-kernel 3.103ubuntu1~20.10.1
Uname: Linux 5.4.73v64 aarch64
ApportVersion: 2.20.11-0ubuntu50.7
Architecture: arm64
CasperMD5CheckResult: skip
Date: Sun Aug 22 20:10:44 2021
DuplicateSignature:
 package:flash-kernel:3.103ubuntu1~20.10.1
 Setting up u-boot-rpi:arm64 (2020.10+dfsg-1ubuntu0~20.10.1) ...
 Error: missing /boot/firmware, did you forget to mount it?
 dpkg: error processing package u-boot-rpi:arm64 (--configure):
  installed u-boot-rpi:arm64 package post-installation script subprocess returned error exit status 1
ErrorMessage: installed flash-kernel package post-installation script subprocess returned error exit status 1
ImageMediaBuild: 20201022
Python3Details: /usr/bin/python3.8, Python 3.8.10, python3-minimal, 3.8.6-0ubuntu1
PythonDetails: N/A
RebootRequiredPkgs: gnome-shell
RelatedPackageVersions:
 dpkg 1.20.5ubuntu2
 apt 2.1.10ubuntu0.3
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)

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1914712, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.