Our Wifi/BT enabled SoMs support dual antenna configuration. It's a recommended and default configuration. If for whatever reason operation with a single antenna is required, please follow this guide.
Starting with BSP 2.8b5 it's possible to configure single antenna operation on boot.
Simply create a file:
options mwifiex single_rf=0x1
Make sure wifi is not enabled by disabling any connections with connman or other Network manager and executing:
$ ip l dev mlan0 down
use iw to set antenna bitmap
$ iw phy phy0 antenna 0x01 0x01
Now you can use WiFi as usual, only MAIN antenna will be used.