I recently purchased a couple of the new EtherFast cards, and yes the default tulip driver didnt work.
http://www.linksys.com actually has tulip.c files for their cards, and they're on the linksys floppies too. After doing a kernel/module compile they work great for me. found at http://www.linksys.com/www.linksys/solution/nos/linux%5Flne100tx.htm i didnt compare them to the ones at http://cesdis.gsfc.nasa.gov/linux/drivers/tulip.html Alex McCool
