Unable to boot Broadcom NetExtreme Gigabit NIC (BCM5761)

[NiKiZe]

snponly.efi and/or undionly.kpxe should work (they are generic and uses UNDI/SNP/NII drivers provided from firmware), if not you are likely to have firmware/BIOS bugs and should report it to HP
You can find standard images built for those at http://boot.ipxe.org

you should never have a "all drivers enabled" build with a .kpxe extension, (.kpxe should only be used with undionly)

Try to start iPXE, press ctrl-B at the first prompt which takes you into the iPXE shell.
here type

Code:

ifstat
dhcp
ifstat

then upload that eighter as text, or as a screenshot (the forum does not allow uploads, so post it elsewhere and then add a link to the image here)

A quick search for "iPXE BCM5761" finds http://lists.ipxe.org/pipermail/ipxe-dev...04476.html and also other links that shows that it is "supported" however we also do know that the tg3 driver which is involved, has a few issues, it is especially visible on iMacs which you can find a lengthy thread about in the forum.