I've made some changes to the firmware a bit more to work much better
with cards with 512k, you can find the binary at
Performance seems to be not much worse than on 1MB cards, except that the
since there is only about 220k left on the board for receive buffers, 256k
blocks won't work (you can do ~= 200k writes just fine though and
get almost the same performance). I suppose I should add something into
the acenic driver for preventing the use of too big blocks...