if File.exists? "#{dir}/var/lib/dpkg/info/grub-efi-amd64.list"
system({'DEBIAN_FRONTEND' => 'noninteractive'}, "chroot", dir, "apt", "remove", "--purge", "-y", "grub-efi-amd64") or raise "Failed to purge grub-efi"
end
- unless File.exists? "#{dir}/var/lib/dpkg/info/grub-pc.list"
+ unless File.exists?("#{dir}/var/lib/dpkg/info/grub-pc.list") && File.exists?("#{dir}/usr/sbin/grub-bios-setup")
system("chroot", dir, "apt-get", "-qy", "update") or raise "Failed to install grub-pc"
system({'DEBIAN_FRONTEND' => 'noninteractive'}, "chroot", dir, "apt-get", "-y", "install", "grub-pc")
end