Booting a NetBSD installer from pxelinux

[Roger Pau Monné <roger.pau%entel.upc.edu@localhost>]

Hello,

I've been trying to boot a netbsd INSTALL kernel from pxelinux, but so
far I haven't got much success. I've tried with 6.0BETA amd64 INSTALL
kernels and it seems to be compiled without MULTIBOOT options, which
makes them useless with pxelinux. I've tried adding "options
MULTIBOOT" to the sys/arch/amd64/conf/INSTALL conf file, but the
resulting kernel is still not booting with pxelinux. I'm using the
following pxelinux configuration:

label netbsd6-install
        kernel mboot.c32
        append rogerpau/netbsd-INSTALL

Which gives "Fatal: not a multiboot kernel." error when using amd64
versions, but with i386 I've got a little bit more success, I'm able
to boot the install kernel, that seems to come with multiboot
activated by default on config file, but since I'm on a serial console
I'm not able to see any output, and the machine reboots shortly after
booting the kernel, to get serial console output I've tried passing
"consdev com1", but I'm not really sure this is the correct syntax to
use with pxelinux.

label netbsd6-install
        kernel mboot.c32
        append rogerpau/netbsd-INSTALL consdev com1

Does someone know how to set the console output for NetBSD kernels
from pxelinux, and why amd64 kernels seem to be not multiboot valid
(at least for mboot.c32/pxelinux).

Thanks, Roger.