Disabling the cable modem portion on Cisco EPC3825 to be used as pure LAN hub?

We upgraded our internet to fiber optic connection and our old 'Cisco EPC3825 EuroDocsis 3.0 Data Gateway' cable modem is now being repurposed as LAN hub on the second floor. It offers wired connections to 2 desktops and wlan acces point. (1Gb vs 100Mb we had previously)

It is also connected to the router proper (sitting next to the 'fiber box') with a 3rd wired LAN connection going between floors. Now, everything is working fine except the Cisco device keeps constantly scanning for cable connection as well and since that isn't connected anymore it is fruitless. So is there any way to stop it from doing that?

This seems to be such weird topic googling wasn't usefull and the user manual doesn't seem to mention it. I suppose I could just leave it like that but that blinking light is annoying me... it probably uses more power too doing that lol