I've tried all day long different settings between the two Netduma. The main one on the first floor is connected to the modem. From that room with a powerline I've connected the second Netduma on the lower floor. Connecting the ethernet cable from powerline to wan port I get many issues and connection is not stable. Connecting Netduma from powerline to ethernet port it looks like the connection is more stable, the only issue I face is that sometimes when I'm browsing Router settings from 192.168.77.1 it's like appear a new instance (with different wan IP and different devices connected) for few seconds, and when this happens I lose internet connection. The most of the time instead I get the same settings as the first floor (with the main Netduma) and I can see even from the lower floor the devices connected from device manager.