I bumped into some hanging problems as well, a few weeks back when I netbooted
a copy of the 1.5_ALPHA2 snapshot for NetBSD/VAX on a couple VS2000 systems.
One, with only 4Mb of memory punted when it ran out of memory before getting
far enough to mount swap, and the other, with 6Mb, would "go away" and hang
shortly after one logged in.  I could run a command or two (e.g. 'ls') but
say running a 'ps' or something else, and it would just sit.  I could ping
the box but no console.  I'm not as advanced as you so I didn't know how
to break out into ddb or the ^T business.  I'll have to try that.  -- Ken