anchor.diff:      echo "initrd /boot/initrd" >> $out/loader/entries/nixos-livecd.conf
       echo "options init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}" >> $out/loader/entries/nixos-livecd.conf
       echo "default nixos-livecd" > $out/loader/loader.conf
  -    echo "timeout 5" >> $out/loader/loader.conf
  +    echo "timeout ${builtins.toString config.boot.loader.gummiboot.timeout}" >> $out/loader/loader.conf
     '';
   
     efiImg = pkgs.runCommand "efi-image_eltorito" { buildInputs = [ pkgs.mtools ]; }
  
positive.code:         }
        ];
  
      # Create the ISO image.
      system.build.isoImage = import ../../../lib/make-iso9660-image.nix ({
        inherit (pkgs) stdenv perl pathsFromGraph xorriso syslinux;
  
negative.code: with lib;
  
  let
    # Timeout in syslinux is in units of 1/10 of a second.
    # 0 is used to disable timeouts.
    syslinuxTimeout = if config.boot.loader.timeout == null then
        0
      else
        max (config.boot.loader.timeout * 10) 1;
  
  
    max = x: y: if x > y then x else y;
  
    # The configuration file for syslinux.
    baseIsolinuxCfg =
      ''
      SERIAL 0 38400
      TIMEOUT ${builtins.toString syslinuxTimeout}
      UI vesamenu.c32
      MENU TITLE NixOS
      MENU BACKGROUND /isolinux/background.png
      DEFAULT boot
  
      LABEL boot
      MENU LABEL Boot NixOS
  