I've got an almost useful serial BIOS redirection on one board here, but
the biggest usability problem is that the NetBSD bootloader starts in
the middle of the screen without clearing it. To work around this, I'm
using the attached patch which adds a "scroll" keyword which just prints
that many blank lines before it does anything else.
Any interest in adding this to the source tree (and of course an
update to share/man/man5/boot.cfg.5)? Or put another way, any active
disinterest in not adding it? :)