Problem with removing essential packages

I am struggling to run fai-setup on an Ubuntu 20.04 machine. I am
using the latest fai packages - 5.10.3ubuntu1 - taken from 22.04. The
problem is related to the removal of "essential" packages, apparently
the --allow-remove-essential option needs specifying somewhere? Can
anyone offer a solution? Here's the relevant chunk of the log...


The following packages will be REMOVED:
  init* libpam-systemd* systemd-sysv* ubuntu-minimal*
The following NEW packages will be installed:
  amd64-microcode btrfs-progs console-common console-data crda curl dialog
  dmeventd dosfstools dracut dump efibootmgr gettext-base grub-common
  grub-efi-amd64-bin grub-gfxpayload-lists grub-pc grub-pc-bin grub2-common
  hdparm hwinfo intel-microcode iucode-tool iw lftp libaio1 libblas3
  libbrotli1 libcbor0.6 libcurl4 libdevmapper-event1.02.1 libedit2 libefiboot1
  libefivar1 libfido2-1 libfreetype6 libfuse2 libgc1c2 libhd21 liblinear4
  liblua5.3-0 liblvm2cmd2.03 liblzo2-2 libnghttp2-14 libnl-3-200
  libnl-genl-3-200 libnuma1 libpcap0.8 libpci3 libpng16-16 libpsl5
  libreadline5 librtmp1 libssh-4 libudns0 libusb-1.0-0 libx86emu2 linux-base
  linux-firmware linux-image-5.4.0-99-generic linux-image-generic
  linux-modules-5.4.0-99-generic linux-modules-extra-5.4.0-99-generic lshw
  lua-lpeg lvm2 mdadm netcat-traditional nmap nmap-common ntpdate numactl
  nvme-cli openssh-client openssh-server openssh-sftp-server pci.ids pciutils
  pigz procinfo psmisc rdate reiserfsprogs rsync smartmontools ssh
  syslinux-common udns-utils usb.ids usbutils uuid-runtime wireless-regdb
  xfsdump xfsprogs zile
WARNING: The following essential packages will be removed.
This should NOT be done unless you know exactly what you are doing!
  init systemd-sysv (due to init)
0 upgraded, 95 newly installed, 4 to remove and 0 not upgraded.
E: Essential packages were removed and -y was used without --allow-remove-essential.
ERROR: 25600 25600
ERROR: chroot /srv/fai/nfsroot apt-get -y -o Dpkg::Options::=--force-confdef -o Dpkg::Options::=--force-confnew --fix-missing install --no-install-recommends nfs-common fai-nfsroot rpcbind rsync lshw procinfo dump reiserfsprogs xfsprogs xfsdump btrfs-progs hwinfo hdparm smartmontools nvme-cli rdate zile numactl udns-utils netcat-traditional nmap pxelinux syslinux-common ca-certificates usbutils pciutils ssh mdadm dracut live-boot- initramfs-tools- dracut-config-generic dracut-network systemd-sysv- curl lftp less ntpdate dosfstools lvm2 psmisc dialog console-common kbd xz-utils pigz grub-pc grub-efi-amd64-bin efibootmgr linux-image-generic return code 100
install_packages: executing chroot /srv/fai/nfsroot apt-get clean
install_packages: executing chroot /srv/fai/nfsroot dpkg --configure --pending
install_packages: executing chroot /srv/fai/nfsroot dpkg -C
install_packages: executing chroot /srv/fai/nfsroot apt-get clean
1 errors during executing of install_packages
ERROR: install_packages had exit code: 3

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