WRT32X Firmware

I have WRT3200ACM on LEDE 18.06.1 and in order to get 5GHz 160MHz working I had to do the same as @TheBeard:
1/ remove kmod-mwifiex-sdio and mwifiex-sdio-firmware as advised in mwlwifi README (simply not modifying country code wasn't enough) + reboot
2/ Set channel to 100 and channel width to 160Mhz.