Acoustic Echo Cancellation (AEC) is not working when playing a voice audio with firmware 6 channel

I recorded my own voice and played it.Meanwhile, I used audacity to record.I found that even on channel 0 there was a distinct sound of my voice, and the AEC didn’t work.But when I play some music, the AEC works better.

Update, the whole AEC is not working.

I did “sudo python dfu.py --download 6_channels_firmware.bin” several times but it did not work.

There was no echo cancellation on channel 0, and background noise was even recorded.

Hi,
I notice that raw data channel 3 and channel 4 are already overloaded, and raw data channel 1 and channel 2 look good, is your loud speaker placed to close to the mic array or the volume too high?
Please try to decrease the playback volume and place the loud speaker a bit far away from the mic array.