One of our users has some EPIA cards. He booted one from the network with the 686 kernel and it worked, so I guess there has to be some kind of difference between what he has and what you have.
The machine that he booted is a SP8000E, with a CPU that Linux sees as VIA Nehemiah (seller says the CPU is VIA Eden), running at 800 MHz. What kind is yours?
We have successfully remote booted from our core with an EPIA M10000 (Nehemiah processor) based logic board.