RealTek cards with an EEPROM (does not work with EPROMs :-)) allow to be reprogrammed with a
DOS tool, so the answer to your first question is: inb and outb.
Of course, that requires that someone has access to the box itself first. As for remote
updatesas the article mentionsyou probably just upload the new firmware through telnet, tftp
or a webinterface. If you are lucky, it may be SSL'ed.
Authenticity? What authenticity? Only a checksum on the file to make sure it was not corrupted
during the transfer but other than that, perhaps a username/password for login, but otherwise,