this is turning out to be retarded and frustrating. first problem was it refused to boot. the last warning of a problem i would get before the system shutdown was nvram: invalid checksum. so it would get to that point and restart - and just keeps repeating. thankfully, this post had some info.
boot> boot -c
UKC> disable uhci
and then store that in the kernel after booting:
# config -e -f /bsd
ukc> disable uhci
but now i get a lot of re0: watchdog timeout errors. the network doesn't really work. it picks up the right IP from dhcp, and it sort of can look up dns, but there is no way to ping or make any sort of connection with the outside world.
this was pretty easy to fix. i had my host change the NIC emulation to use intel rather than the realtek driver. network issues went away. i still had to disable uhci to boot openbsd, though.