Intel NUC platform firmware -- no serial I/O support?

["Laszlo Ersek" <lersek@redhat.com>]

Hi List,

my toolbox has been extended with an Intel NUC, the base kit model being
NUC8i3PNH. The NUC has a serial port connector on the back, and indeed
Serial I/O works fine once an OS starts.

However, the UEFI platform firmware seems to have no support for Serial
I/O. I've built a fresh UEFI Shell binary from edk2 master and poked
around in the protocol database, with "drivers" and "dh". The necessary
drivers seem to be included, however they do not appear to bind the
hardware that's inside the chassis. ("connect -r" makes no difference in
this regard, so it's not just BDS policy.)

Interestingly, the related drivers are all called "AMI ...", which I
find somewhat strange on an Intel-branded NUC. I don't know whom I
should be addressing with my question in the first place. Just to be
sure, I'm CC'ing a bunch of randomly picked @ami.com email addresses
from my edk2-devel list archive.

I can provide more details if needed, but first I'd like to ask if *any*
firmware update exists for this kit -- NUC8i3PNH -- where the platform
firmware can drive the serial port. My goal is (of course) completely
headless operation of the NUC; ideally, that would cover the UEFI
console too.

Right now, I need to connect an HDMI monitor and a USB keyboard+mouse to
the NUC just to get into the Setup UI / UEFI Shell.

Thanks!
Laszlo