anchor.diff:  
           `null` means no limit i.e. all generations
           that were not garbage collected yet.
  +      '';
  +    };
  +
  +    extraInstallCommands = mkOption {
  +      default = "";
  +      example = ''
  +        default_cfg=$(cat /boot/loader/loader.conf | grep default | awk '{print $2}')
  +        init_value=$(cat /boot/loader/entries/$default_cfg | grep init= | awk '{print $2}')
  +        sed -i "s|@INIT@|$init_value|g" /boot/custom/config_with_placeholder.conf
  +      '';
  +      type = types.lines;
  +      description = lib.mdDoc ''
  +        Additional shell commands inserted in the bootloader installer
  +        script after generating menu entries. It can be used to expand
  +        on extra boot entries that cannot incorporate certain pieces of
  +        information (such as the resulting `init=` kernel parameter).
         '';
       };
   
  
positive.code:       --disallow-untyped-defs \
        $out
    '';
  in {
  
    imports =
  
negative.code:     ];
  
      system = {
        build.installBootLoader = finalSystemdBootBuilder;
  
        boot.loader.id = "systemd-boot";
  
  