anchor.diff:                diskImage=$out/disk.img
                 ${qemu}/bin/qemu-img create -f qcow2 $diskImage "60M"
                 ${if cfg.useEFIBoot then ''
  -                efiVars=$out/EFI_VARS.fd
  -                cp ${efiVars} $efiVars
  +                efiVars=$out/efi-vars.fd
  +                cp ${efiVarsDefault} $efiVars
                   chmod 0644 $efiVars
                 '' else ''
                 ''}
  
positive.code:           '';
        };
  
      virtualisation.bios =
        mkOption {
          default = null;
  
negative.code:     else if pkgs.stdenv.isAarch64 then "${pkgs.OVMF.fd}/FV/AAVMF"
      else throw "No EFI firmware available for platform";
    efiFirmware = "${efiPrefix}_CODE.fd";
    efiVarsDefault = "${efiPrefix}_VARS.fd";
  
    # Shell script to start the VM.
    startVM =
  