Even if you check the Dual 4G Networks that doesn’t actually seem to do anything so you to go into the secret menu and enable it. I wish it just worked out of the box. It probably will eventually. 1) Go to the dialer and enter: *#800# Select Enter Go to Logkit Swipe down to function switch Tick VoLTE and/or VoWiFi switch Reboot Once that is complete, you can toggle the “Dual 4g” networks switch and actually get the Wifi-Calling & VoLTE options available for your 2nd Sim.