6.1.4 : fresh install : boot device <not found>

[Mayuresh Kathe <mayuresh%kathe.in@localhost>]

hello,

i messed up my 6.1.4 on amd64 system, so did a fresh install.
everything went well, but while first boot, it showed;
boot device: <not found>
root device 

it just stayed put till the point i installed another system
and then re-installed netbsd 6.1.4, this time, everything
went well, including the first boot.

i am sure i have performed every step, just can't go wrong with
netbsd. :)
makes me wonder why the system just stopped at "root device".

is there anything i could have done to find out what went wrong?

thanks,

~mayuresh