anchor.diff:    users   = map (x: x.user  or "''") contents;
     groups  = map (x: x.group or "''") contents;
   
  +  basePaths = [ config.system.build.toplevel ]
  +    ++ lib.optional copyChannel channelSources;
  +
  +  additionalPaths' = subtractLists basePaths additionalPaths;
  +
     closureInfo = pkgs.closureInfo {
  -    rootPaths = [ config.system.build.toplevel ] ++ (lib.optional copyChannel channelSources);
  +    rootPaths = basePaths ++ additionalPaths';
     };
   
     blockSize = toString (4 * 1024); # ext4fs block size (not block device sector size)
  
positive.code:   # utils, but changes the hash of the image when the sources are
    # updated.
    copyChannel ? true
  }:
  
  assert partitionTableType == "legacy" || partitionTableType == "legacy+gpt" || partitionTableType == "efi" || partitionTableType == "hybrid" || partitionTableType == "none";
  
negative.code:       ${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 ''
  