The server was an HP ML110 g5 series machine.
This machine comes with a riser slot for the Lights out card, but the card is not present. I dont know if that means that there is still some chipset on the mobo or if there is nothing present at all.....
I've not had an ML110 G5 in front of me to know for sure (all of the HP we have currently are G4 or older). On many of the older HP/Compaq, iLo was there (in part or whole) even if you didn't purchase it. I have seen others (both iLo and Dell DRAC) that have issues with the "shared nic" options and any remote USB emulation (floppy or USB).
Just recently when trying to image several Dell PE2950's for a project, we had a issues booting anything USB. In the end it turned out to be the DRAC; once it was removed USB booting was normal. Most likely it was the "virtual floppy" and "virtual cd-rom" that the DRAC creates.