Just finished setting up networked units on my desk. It's 103 F in my garage now, ain't doing it there, LOL.
After the update, you don't get the Network tab until the unit recognizes that Network is connected, THEN you have wait a little longer for the units to recognize each other so they will be displayed in each unit's Network Source Setup. One of my units had not been networked after the update so it had no Network menu until I just connected it to another unit.
If that doesn't happen, your Ethernet connection has failed or if you have an Ethernet Switch, it isn't powered.
Failed Ethernet can be a damaged connection pin or a conductor in the cable itself from being put in a tight turn and that turn flexed.
Anything more than that, it would be a software glitch.
AND the G2N models seem to be the most glitchy units just going back in history of those models. I don't have any networkable G2N's so I haven't had the pleasure of dealing with them.