When you added the mac2= did you also try editing the synoinfo.conf file to manually set it as active? It should then show under Hardware and Power with a check box for WOL. Maybe you can use that to see if the card is accessible on the network?
The network card shows up in Network, and it shows LAN2. I don't see anything in synoinfo.conf that says it's disabled. I can't change anything in synoinfo after adding mac2 because as soon as I add mac2 I lose access to everything.
OK, new information maybe. I don't have mac2= added because I still need access to my files at the moment. However, when loading up syno assistant, it shows "2 servers" one for each nic. The status of each server is: the 1gb nic is ready, the 10gb nic is connection failed. I can only assume that the reason this isn't working is something to do with the mac2= problem. Unfortunately I am not a linux master, so I really don't know what more information I can provide.