grub-luks2-improved-stable/grub.install

#!/bin/sh

post_upgrade() {
  # We used to package /boot/grub/grub.cfg, but there is no reason to.
  # Remove the file from package, but move real file back in place.
  if [ ! -f /boot/grub/grub.cfg -a -f /boot/grub/grub.cfg.pacsave ]; then
    mv /boot/grub/grub.cfg.pacsave /boot/grub/grub.cfg
  fi

  # Give a hint to update installation and configuration one after another.
  cat <<EOM
:: To use the new features provided in this GRUB update, it is recommended
   to install it to the MBR or UEFI. Due to potential configuration
   incompatibilities, it is advised to run both, installation and generation
   of configuration:
     # grub-install ...
     # grub-mkconfig -o /boot/grub/grub.cfg
EOM

  # return if old package version greater 2:2.06-0...
  (( $(vercmp $2 '2:2.06-0') > 0 )) && return

  if [[ -e /sys/firmware/efi/efivars ]]; then
    cat <<EOM
:: Grub does no longer support side-loading modules when secure boot is
   enabled. Thus booting will fail, unless you have an efi executable
   'grubx64.efi' with bundled modules.
EOM
  fi
}

post_install() {
  cat <<EOM
:: Install your bootloader and generate configuration with:
     # grub-install ...
     # grub-mkconfig -o /boot/grub/grub.cfg
EOM
}