Both wired and wifi

Pi 2B with OSMC
Is there a way to have both wired and wifi connected at the same time but on different networks?
Use case: I have an internal offline network from which I’m playing content connected on LAN but would like to have the Pi connected to a WiFi network in order to get updates, art for content etc.
In Windows this is doable by setting metrics on the LAN and WiFi adapters, not sure how to do this for the Pi.

Yes. This should be possible

Effectively, you want all traffic to go via WiFi, except for local content, which goes via ethernet.

The “trick” will to persuade connman to reliably set the default route via wlan0. Perhaps @sam_nazarko can advise. (Note the word reliably.)

As long as wlan0 and eth0 are on different subnets, I would expect connman to add an additional route for all traffic to the (wired) LAN subnet. If it’s not there, it can be added manually.

Well, the DNS Server should be in the LAN (Except if you work with IP Addresses in your local LAN -> in the configuraitons). The default route should point through the WiFi interface, while there should be a route (which is added by default) to the local ethernet interface (as soon as an Ip is assigned).
So yes, I tend to use that setup at home on my work computer when the company VPN blocks everything.

That is correct, this is what I’m aiming for.

There is one method that might send the default route through the WiFi interface though, in my experience, it hasn’t proved to be 100% reliable.

In file /etc/connman.conf change line

PreferredTechnologies=ethernet,wifi

to

PreferredTechnologies=wifi,ethernet

Reboot the device multiple times and see if the default route is always through wlan0.