Does it got a boot ROM? That's where those get shadowed.

BitWrangler wrote on 2021-06-12, 03:56:

Does it got a boot ROM? That's where those get shadowed.

There's no physical socket for one but it may have one built in. Thoughts on disabling it?

That would be my guess as well, the later Pro/1000 cards have a fairly extensive boot ROM and PXE client built in. I wouldn't be surprised if it was significantly larger (in bytes) than the old style 32kb socketed ROMs on earlier cards.

There will be an embedded eeprom on the card somewhere. It's probably a tiny part compared to the old dip28 designs.

In later Intel PXE client s you could enter a setup interface. Try some control codes while the boot agent text is shown: control-a and control-s were the common ones from memory.

I remember having a DEC DE205 (ISA ethernet) that could be configure to use up to 32k (in high memory) as a buffer to improve network speeds.

Maybe your card is doing the same thing?

So the solution was indeed inside the card's setup program accessible with ctrl-s.

It was a little counterintuitive, but under boot options choosing "try local drives only" and saving resulted in removing the PXE ROM from memory

The PXE client got fatter and fatter over the years - the initial versions had support for ipv4 via dhcp and a minimal tftp client and not much else. By the time you get to dual mode UEFI/legacy clients you've got ipv4 and ipv6 built in, http as well as tftp boot file support and a whole load of enhancements for supporting larger tftp transfers and fragmented packets across subnets.

Part of my day job is implementing and managing the network boot and imaging service for Linux workstations and servers in our university; over the years I've seen the quality of the network boot rom differ massively from implementation to implementation, but the Intel one was always solid. One oddity with some of the dual-mode UEFI systems in the last few years is that the UEFI PXE clients are often not as feature complete or bug-free as the PXE client available in legacy mode - a whole suite of Dell workstations simply couldn't complete the initial DHCP request and load the initial imaging binary from a tftp server when that tftp server was on a different subnet, yet drop those same machines back to legacy mode and the old dependable Intel PXE client just worked.

Of course, in legacy mode you don't get boot support for NVMe devices, so that wasn't a workable solution!