recent com* changes seem to break cobalt's kernel / serial console

Hi!

After

  http://mail-index.netbsd.org/source-changes/2008/10/25/msg211704.html

-current kernels compile fine again for my cobalt qube 2, but hang up
during booting / running the /etc/rc stuff. Last message displayed
looks like

  com0 at mainbus0 addr 0x1c800000 level 3: st16650a, working fifo
  com0: console
  [...]
  boot device: wd0
  root file system type: ffs
  root on wd0a dumps on wd0b
  /: replaying log to memory
  /: replaying log to disk

Then the machine hangs up and shows no more reaction, no entry into
ddb via serial BREAK signal possible.

Does anybody else see this on cobalt (or other serial console)
machines?

Reverting to an older kernel before these com* changes makes my qube
booting/running normally again.

Anything I can test to narrow this problem?

Markus.