pxebooting with GRUB 2

[Daniel Kahn Gillmor]

Hi folks--

I've searched high and low for documentation about how to get PXE
booting working with GRUB 2, but i haven't had much luck.  Can anyone
give me pointers?

What i've done so far
---------------------

I found a brief mention on the wiki [0] and followed those
instructions: "cat pxeboot.img core.img >pxegrub" does create a
PXE-bootable grub image, but once the image is loaded, GRUB 2 doesn't
seem to be capable of downloading other files over the network (this
includes being unable to download its own config file).

I get dropped into a "rescue GRUB shell", which appears to be only
useful for pulling files off of a local disk -- but that sort of
defeats the purpose.  Here's what i see on the screen after the pxe
boot:

Welcome to GRUB!

Entering into rescue mode...
grub rescue>

looking at the logs of my TFTP and DHCP servers, i see the initial
(boot ROM-generated) PXE interaction of a
DHCPDISCOVER/OFFER/REQUEST/ACK handshake, and the initial TFTP
download of the pxegrub file itself, and then nothing.

What else do i need to to enable pulling files via TFTP?

i've successfully pulled files off a TFTP server with a patched GRUB
Legacy [1], but i'd like to support and use GRUB 2 if possible.


Details
-------

FWIW, the above attempt was done using a Via Rhine NIC with functional
PXE boot ROM.  the version of GRUB 2 that i tried is the one in debian
unstable at the moment (1.95+20070828-2), and i was using the core.img
generated on this same debian unstable system that initially boots
from a local disk.  Maybe i need to regenerate a different core.img
somehow?


Final Questions
---------------

Is there documentation somewhere that i missed?  I'd love to get a
pointer or two if it's out there.

I'm also happy to help debug this, and to write up my notes on the
wiki, if folks think that'd be useful.

What next steps should i take to get network booting working?  Do you
have any advice?

Thanks for making this useful tool, and for making it free.

Regards,

       --dkg

[0] 
http://grub.enbug.org/TestingOnX86#head-27ab6e1ddfd82d0c72737201a4e17e3a91ea1a24
[1] http://os.inf.tu-dresden.de/~adam/grub/0.97/pxegrub-0.97-os.3.gz