When I didn't have the 'flags 1' argument in my config.new style config
file, the serial line to my modem (which is on the 3rd port of the
4-port card) would not work properly--anything which tried to talk to it
would wait on ttyoutput.

When I put the 'flags 1' back in and built a new -current kernel, then
things worked just fine.

Something is obviously amiss somewhere; I assumed that since putting
'flags 1' back in fixed the problem, that it was the problem.  Is there
something else broken instead?

==John