@RedRoger 2nd unit is link to the first deco...in such way, it can't be connected to 5GHz? If this is the only way to configure it, then the 2nd unit doesnt serve any purpose at all.

Hi I had 2 units of deco M4. 1st unit connected to modem installed at 1st floor living room, 2nd unit installed at 2nd floor living. Im running at 300mbps broadband. When I test speed using laptop...