@jestabro Thanks for that!

OK, a little digging around in the grub configs led me to a "workaround" solution for the serial console problem after the machine is booted.

OK, the grub serial config described here got me as far as seeing the Grub selection screen at boot time.

I replied to jestabro via email a couple of hours back, but noticed that it didn't show up here. For the benefit of anybody else interested in this bug I'm cutting and pasting the email below: