Just found mail from Frank van der Linden dated 3 Aug 1997!

        - compile a kernel with:
                - makeoptions   DEBUG="-g"
                - options KGDB, KGDBDEV=0x0801, KGDBRATE=38400
                                ^^^^^^^^^^^^^^
                                makedev(commajor, 1)

        - boot that kernel on the machine that you want to debug.
          use the -d option when booting to have it drop into kgdb
          right away.

        - on the other machine (assuming that you did the compiling there),
          go into the compile dir for the kernel on the other machine
          and do:
                - you should probably have 'softcar' set for the serial line
                - gdb
                - file netbsd.gdb
                - set remotebaud 38400
                - target remote /dev/tty03

So, will try that...

Cheers,

Patrick