The kudzu process will hang the boot procedure when the machine is configured to use a serial console and the rc?.d/S??kudzu init script is run. Output is a series of spaces/tabs every few seconds and any attempt to exit/abort (Ctrl-C, Ctrl-X, etc) does not work. The machine does not continue to boot but instead stays in this state untill it is power cycled. Workaround is to remove /etc/rc.d/rc?.d/S*kudzu on systems booting with a serial console. A more perminent suggestion would be to check for a serial console and abort in the init script; check for serial console and abort in kudzu; or check for serial console and if present skip serial tests and proceed in a text based mode.
Duh. I'm surprised none of the sparc-types beat me over the head about this before. Fixed in CVS; will be fixed in the kudzu-0.24 release.