Boost signal on ReSpeaker USB AGC

I want to boost signal from 0.005V to 0.2V by increasing AGCDESIREDLEVEL (0.005 default) and AGCMAXGAIN (31.6 default) but I don’t see any effect. Has anyone been successful to boost the signal level?
I’m running the USB respeaker (6-ch software) from ubuntu, using and dev.write from After I write a parameter, the read indicates the new value. BUT I get no change to Ch0 or Ch1-4 levels no matter if AGCONOFF is 0 or 1, always -46dB (0.005V) on Ch1 and -54dB on Ch0.