2.4 G WiFi has gone to Sh@T

After the latest firmware down load 2.4 wiFi has gone nuts. Video cams. that worked flawlessly for years now don’t.
It evens seams to efect ethernet cable devices. I have tried all the obvious, the only thing I have not tried is to go back on firmware because I can’t find it after form downgrade.
WTF is goin on? Two firmware upgrades ago this crap started with 2.4 G wifi.
I"m literally the only one with wifi where I live.
Please set me up with firmware 7.0.Something. the old fw was better.

You don’t mention the device you are using but if you go to System → Reboot may be able to select any older FW in there you had before.

FWIW, wifi (both 2G and 5G) works fine for me on multiple B20Xs using latest FW.