What brand \ part number eUSB are you using?
I had an issue on a newer revesion eUSB device. (different motherboard, same generation)
The newer device did not come up in set-up with the correct vendor ID information. (hardware compatability issue.)
I haven't actually purchased any eUSB devices yet for the MFS2600KI board since Intel hasn't released any tested devices in the HCL for this compute module. I am assuming that some devices that meet the specs would work, but have been hoping to see something official from Intel before I invest the money.