The only reliable way to prevent eavesdropping is to physically break continuity of all voice coils in the device. Entrusting a black box chip to do this on yo

The only reliable way to prevent eavesdropping is to physically break continuity of all voice coils in the device. Entrusting a black box chip to do this on your behalf is more risky than there being a physical kill switch somewhere which all the voice coils pass through. There's certainly going to be a way for the chip to be told via software to reconnect the coils, though you may not know how yourself.