Hi,
First of all I need to admit that I'm not sure if I've actually tested with anything except the default 2k per socket so it's quite possible something isn't correct there. The phrase but not work isn't much help though, do you have any other leads or hints, what does it do or what does it not do?

With that said, one thing I do see is
Code:
W5100_S0_RX_START CON $6000 'Start adress of Socket 0 (not changeable)
W5100_S0_RX_END CON $7FF9      ' <----- Shouldn't this be 7FFF?
W5100_S0_RX_MASK CON $1FFF 'Mask value for 8k
but I'm not sure if that IS the only problem or not.

/Henrik.