You have to dump a private header/ROM from a legitimate cartridge using Gateway's Launcher.dat (you don't need a Gateway). You can just use one private header for every ROM you intend to go online with and that would be a lot safer than using the standard template or public headers.
If i extracted a private header, then can I patch the whole orginal template, using no ban no sky with my private header bin? Then just write games to sd card after patching the whole template? No need to go patching one rom at a time right?