package u-boot-rpi:arm64 2021.01+dfsg-3ubuntu0~20.04.3 failed to install/upgrade: installed u-boot-rpi:arm64 package post-installation script subprocess returned error exit status 1

[Stephen Pace]

Upgrade from 19 to 20 and failed.

https://bugs.launchpad.net/ubuntu/+source/u-boot/+filebug/5c731cf4-0469-11ec-a586-0025b3df357a?field.title=package+u-boot-rpi%3Aarm64+2021.01%2Bdfsg-3ubuntu0~20.04.3+failed+to+install%2Fupgrade%3A+installed+u-boot-rpi%3Aarm64+package+post-installation+script+subprocess+returned+error+exit+status+1

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: u-boot-rpi:arm64 2021.01+dfsg-3ubuntu0~20.04.3
Uname: Linux 4.19.126-v8+ aarch64
NonfreeKernelModules: nft_counter nft_compat nft_chain_nat_ipv4 nf_tables veth xt_nat nf_conntrack_netlink nfnetlink xt_addrtype br_netfilter xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat xt_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter overlay openvswitch nsh nf_nat_ipv6 nf_nat_ipv4 nf_conncount nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 brcmfmac brcmutil cfg80211 rfkill bcm2835_codec bcm2835_v4l2 v4l2_mem2mem bcm2835_mmal_vchiq v4l2_common videobuf2_dma_contig videobuf2_vmalloc raspberrypi_hwmon hwmon videobuf2_memops videobuf2_v4l2 videobuf2_common zfs videodev vc_sm_cma media rpivid_mem uio_pdrv_genirq uio zunicode zlua zcommon znvpair zavl icp spl zlib_deflate fuse binfmt_misc ip_tables x_tables ipv6
ApportVersion: 2.20.11-0ubuntu27.18
Architecture: arm64
CasperMD5CheckResult: skip
Date: Mon Aug 23 14:18:15 2021
Dependencies:

DuplicateSignature:
 package:u-boot-rpi:arm64:2021.01+dfsg-3ubuntu0~20.04.3
 Setting up u-boot-rpi:arm64 (2021.01+dfsg-3ubuntu0~20.04.3) ...
 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 u-boot-rpi:arm64 package post-installation script subprocess returned error exit status 1
Python3Details: /usr/bin/python3.8, Python 3.8.10, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: N/A
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.6
SourcePackage: u-boot
Title: package u-boot-rpi:arm64 2021.01+dfsg-3ubuntu0~20.04.3 failed to install/upgrade: installed u-boot-rpi:arm64 package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to focal on 2021-08-23 (0 days ago)