Intel PRO/1000MT and HP4

On Thursday I installed the imaging files from HP4
(ZDM7SP1_HP4_20070417_Img_Resource_Files) so that I could start working on
images for our new Optiplex 740's. Works great...

However, now our GX270's won't boot from PXE. They can download the files
they need via TFTP and they start the boot process, but it dies while
requesting a DHCP address. From there you get the blue Linuxrc screen,
where I've checked that the driver has loaded (e1000 for Intel PRO/1000).
Indeed, eth0 is listed in System Information, but it doesn't seem to
respond.

All our other machines boot PXE fine with HP4 (GX260, GX280, GX620, and
the new 740). Funny thing is, according to Windows the GX260's and GX270's
have the same card.

Anyone have any thoughts?