I have three X20s, the first connected to the WAN, the second connected to the first via Ethernet and a third connected over WiFi mesh. The second is close to the first so it can mesh if it tries, but there are some brick walls in the way so network performance is much better over Ethernet.

Today I updated to 1.2.0. The second initially reported a weak WiFi mesh link to the first, and network performance reflected that. Rebooting would cause it to report an Ethernet link intermittently, but there was a huge amount of packet loss making it mainly unusable.

I tested the Ethernet cable by connecting a laptop in place of the second X20, so it was connected directly to port 2 of the first X20 (port 1 went to the WAN). The laptop failed to report any Ethernet connection. Next, I removed the Ethernet from port 2 of the X20 and connected it directly to the modem (just to test the cable, not IP). Within a few seconds, the laptop reported the Ethernet connection was up. I plugged it back into port 2 and it remained down. I then disconnected the WAN from port 1 and connected the laptop instead, which reported the Ethernet was again up. So I decided to reconnect the second X20 in place of the laptop and connect the WAN on port 2 of the first X20. Everything worked again.

This might be a complex report, so I will summarise:

Before:

First X20 - Ethernet 1 to WAN, Ethernet 2 to second X20

Second X20 - Ethernet to first X20, also Ethernet to a PC (probably irrelevant, not described above, but mentioned for completeness) (unfortunately I don't remember which way round the ports were connected)

Third X20 - happily meshing

Update to 1.2.0, anything on second X20 has packet loss, first X20 worked fine.

After:

As above, but swapped ports on first X20.