Immediate reboots on amd64 after upgrading to current

Hi,
I was running 5.4 (amd64) but was looking to get my nForce4 nic
working.  I heard about the nve driver in current and so I upgraded to
current.

I followed the handbook instructions of essentially make buildworld,
buildkernel, installkernel etc..  When I rebooted however I found that
the new kernel immediately reboots after selecting any of the options
on the boot menu (safe mode, normal, single user, etc).

I've restored my system to 5.4 (it didn't have anything important
anyway) but I was wondering what actually went wrong..

Is the 6-current broken at the moment?  (unlikely as it seems like
quite a severe break)

Did I miss something to do with reconfiguring the boot process?

What should I look out for when I try again..?


-- 
Paul Richards