anchor.diff:        ${if copyChannel then "--channel ${channelSources}" else "--no-channel-copy"} \
         --substituters ""
   
  +    ${optionalString (additionalPaths' != []) ''
  +      nix copy --to $root --no-check-sigs ${concatStringsSep " " additionalPaths'}
  +    ''}
  +
       diskImage=nixos.raw
   
       ${if diskSize == "auto" then ''
  
positive.code:   users   = map (x: x.user  or "''") contents;
    groups  = map (x: x.group or "''") contents;
  
    closureInfo = pkgs.closureInfo {
      rootPaths = [ config.system.build.toplevel ] ++ (lib.optional copyChannel channelSources);
    };
  
    blockSize = toString (4 * 1024); # ext4fs block size (not block device sector size)
  
negative.code:   # utils, but changes the hash of the image when the sources are
    # updated.
    copyChannel ? true
  
  , # Additional store paths to copy to the image's store.
    additionalPaths ? []
  }:
  
  assert partitionTableType == "legacy" || partitionTableType == "legacy+gpt" || partitionTableType == "efi" || partitionTableType == "hybrid" || partitionTableType == "none";
  