{ pkgs, lib, system, windows, ... }:
let
  upstreamISOsJSON = lib.importJSON ./upstream.json;

  fetchUpstream = name: src:
    if (src.type or "") == "fetchgit"
    then pkgs.fetchgit { inherit (src) url rev hash fetchLFS; }
    else pkgs.fetchurl { inherit (src) url sha256; };

  upstreamISOs = lib.mapAttrs fetchUpstream upstreamISOsJSON.${system};
  images = (import ./images.nix) { inherit pkgs lib system windows upstreamISOs; };
in images