new 7I80HD not found

Well, got a 7i80 and am trying to get it going.
Linuxcnc all installed. new install on new SSD
7i80 attached with a known good cat cable. 5v on the DC in. correctly.... pins all in default positions.
Docs say default IP is 192.168.1.121.
set the IP4 address on the port to that, and netmask 24, gateway 192.168.1.1. should work???
running mesaflash. 'mesaflash --device 7i80'
no good results. 'No 7I80 board found' no matter what I try. even explicitly giving the IP
waz up with this?

little help please.....pcw??? or anyone.

What does

ip a

report?

Edit: you must set the host address to an address different than the 7I80
but on the same subnet, say 192.168.1.100