If the ethernet port is set to obtain an IP address using dhcp, then this is most likely what is failing (since there is no dhcp server active to provide an address). Chances are netstack has started, just the interface is failing to set up corrrectly.

You can see if netstack has started using taskmanager (located in sys:utilities) - it will show up as "netstack kernel".
You can get detailed info on what state the network is in using netstat (located in sys:tools).

From the command line, you can attempt to reconnect and obtain an IP address using:

offline eth0
online eth0

(assuming your interface is called eth0)

A script attempting reconnection periodically (eg every 2 minutes) in the case dhcp fails would certainly be possible, but if you have to go turn on the wireless bridge anyway, I guess using the command line is just as easy.

Alternatively, if you set up a static IP address, it should just start working once the bridge is switched on with no intervention needed on the MorphOS machine.

To set up a static IP address see here.

[ Edited by boot_wb 18.06.2016 - 13:55 ]