I am looking for a compatible USB NIC that will PXE boot. I have tried a number of StarTech ones - none are seen in the bios. I have also tried ipxe via rom-o-matic but again no joy.
I was given an idea by a surface pro 4 owner who had a similar issue. He used a specific chipset USB NIC - SMSC - LAN7500 after hunting on ebay for a cheap NIC I found a startech USB21000S2
Not only did this work flawlessly but it also got detected by the BIOS - no ipxe USB stick required. Here are the pictures for the BIOS and booting: http://imgur.com/a/eaZbl
In short, yes it is possible with a LAN7500 USB NIC and a chipset is supported natively by the BIOS.
edit: im going to set this as the answer as I found the details myself. Ive left this here for others as I suspect this will also work for other BIOS too.
Thanks for posting.
Apparently it does not appear to be a way to PXE boot this computer, however, here is one workaround: http://dell.to/2qHBWV1
#IWork4DellWould you like to be a Dell Community Rockstar?
Alas my XPS11's are running Ubuntu so I cannot use a WinPE boot (we use FOG as a PXE deployment mechanism). I'll probably bin these XPS11's off as a non-starter if there aren't any USB NICs that work from POST.