I used the following to set up a serial console:

installboot -v -m i386 -o console=com0,speed=57600,timeout=10 /dev/rwd0a 
/usr/mdec/bootxx_ffsv2

I have just noticed that the machine hangs at the NetBSD boot prompt 
when the serial cable isn't plugged in (in this case, in to my laptop 
and using terminal emulator software). It's not locked up, it just 
refuses to actually do the timeout countdown and boot the kernel until I 
plug it in, hit enter, which brings me a prompt, and type 'boot'.

Is there something simple I have missed? I can't have the cable plugged 
in to my laptop 24/7, as my laptop happens to sit on the other side of 
the room.
-- 
Mark Cullen <mark.r.cullen@gmail.com>