Colour me impressed! I would have expected a digital pin be used to control the microphone in software, which I wouldn't have been nearly as satisfied to see. Really nicely presented breakdown too.
> Colour me impressed! I would have expected a digital pin be used to control the microphone in software
Yup, and even if the same pin drives both the LED and the microphone power switch, there's various attacks (e.g. high frequency PWM 75% duty cycle-- enough to light the LED to nearly full brightness, but also probably enough to keep the mic bypass capacitor nearly fully charged).
Since the SOC can only turn off mute, and not turn it back on, any attempt to eavesdrop would leave evidence (a mute LED left off).
