No kernel messages displayed during boot

[Dmitry Karasik]

Hello,

My 6.2-STABLE crashed today, and when I rebooted it, a very
strange effect appeared: from the second the kernel took 
over, immediately after loading all .ko files, no text
was printed in the console. The system booted though, 
and the next text was printed to the console was the
login prompt. The screen didn't went blank, just all
kernel messages and output of /etc/rc* wasn't there -- all
was printed on the screen was FreeBSD boot menu, and login
prompt.

I've re-run 'make installworld' and 'make installkernel' (as
I had leftovers from recent buildworld), - didn't help. I've
tried to power down the machine (suspecied video card trouble),
I've resetted BIOS, I've even disabled com port in BIOS (because
the behavior looks like booting on serial console) -- nothing,
absolutely nothing changes it. 

When I tried to boot in single-user mode, the prompt was never
displayed at all, which fact indeed makes me think alogn the path of
the wrong boot console. I've removed /boot/loader.conf, and double-checked
that /boot.config isn't present - didn't help. 

My question is therefore, what cause of this effect might be?
Or, if noone would be able to answer this, how I would print messages
from kernel (I'd recompile it for that purpose) to identify which
device it picked up for console IO -- and especially, how I print
that either to a file, or directly to /dev/console?

-- 
Thank you,
	Dmitry Karasik