Can't set FAST 5688W 2.4GHz wifi to 20MHz, it keeps setting to 40MHz instead

[ledlamp]

When I change the 2.4GHz Wi-Fi bandwidth to 20MHz, save it and refresh, I find that it's set to 40MHz instead!

I can change it back to auto or explicitly set it to 40MHz, but whenever I set it to 20MHz, it actually sets to 40MHz.

I am however able to set the 5GHz to 20MHz, 40MHz, 80MHz, or Auto. But I want to set the 2.4GHz to 20MHz.

[ledlamp]

Oh. Somehow I got it on 20MHz now. I tried several times before and it kept doing 40MHz. Only difference I did the last time is explicitly setting each channel and bandwidth of each band. 🤷

[ledlamp]

btw it seems that after changing wifi settings the wifi is broken. It's broadcasting but I fail to connect. So I have to reboot it

[ledlamp]

WTF? After unplugging power it changed all my settings.

And 160MHz??? That's not even an option in HINT control.

Kinda seems like it's not designed to be set at all... After the power is lost it changes to whatever it wants..