OK, I spent a few desperate days at this but I'm proud to announce that I've ported Sqward's uIP to this adapter, incl. the 16-bit (word) NE2000 transfer mode. You can find my work here: https://bitbucket.org/mikro_sk/uip-tools/branch/16-bit
I need to clean it up and perhaps include a dynamic detection for both cards (cartridge & expansion slot).
upload from Falcon @ 16 MHz: 135 KB/s
upload from Falcon @ 32 MHz: 161 KB/s
download to Falcon @ 16 MHz: 170 ~ 180 KB/s
download to Falcon @ 32 MHz: 199 ~ 205 KB/s
upload from Falcon @ 16 MHz: 140 KB/s
upload from Falcon @ 32 MHz: 166 KB/s
download to Falcon @ 16 MHz: 180 ~ 190 KB/s
download to Falcon @ 32 MHz: 210 ~ 222 KB/s
32 MHz means pure CPU frequency, no fast ram or anything else.
I'm quite surprised how little impact the 16-bit mode has but it's perhaps because the send/recv routines are optimised to death and packet size is relatively small so unrolling move.b vs. unrolling move.w (in a cache friendly jump tree) doesn't make such a difference.
Now I'd like to consolidate EtherNE sources, so we get both STiNG and MagiCNet/FreeMiNT drivers within the official distribution in a next version. However I expect lower performance there. :-(