UI config file is a json format with following possible parameters: Note: All top level keys must be optional. "download_screen" (depends on "network_screen") Used to show a window where user can input a custom URL from which a file can be downloaded and placed in a custom location in the installed system. "title" (required) A short title to identify this screen "intro" (required) An brief 2 line intro of what URL you are requesting the user to input "destination" (required) String; Path to where in the installed system you would like to see this file