Olimex1 make splendid PIC based ethernet boards, but supply them with an older version of the Microchip TCP-IP stack. It's relatively easy to compile more recent versions of the stack for Olimex hardware, but some work is needed to access the on board Atmel flash memory.

All the hard work of writing the Atmel flash interface has already been done by Olimex in the stack they supply with the board, but that's version 4.02 of the stack.

However it makes Generating the patch from scratch is relatively easy: just compare the TCP-IP stack supplied by Olimex with the same stack from Microchip, then tweak the resulting diff a bit. Alternatively, just download the patch from here.

The patch has been tested on version 4.16 of the TCP-IP stack, running on the Olimex MAXI-WEB3. It's probably worth pointing out that this stack is probably too big to use on the PIC18F25J10 based Olimex MINI-WEB, which has only 32kB of program memory.