[dev-il]

> The only problem remaining, on this particular device, is direct connection of physical sensors (microphone, GPS, etc) directly to the modem

is that even the case of the microphone? My understanding was that - independently of the possibility to turn the microphone and modem off with kill switches - all audio data to the modem comes via I2S from the SoC anyways, i.e. that the microphone is NOT directly connected to the modem but to the SoC (possibly via a separate audio codec Chip) and that the SoC serves the modem via I2S whatever audio data the user pleases (whether that be from the microphone or whatever else).

[MartijnBraam]

Yes, the modem can't talk to anything, it's only connected to the SoC with the i2s audio bus and the usb bus, the SoC controls what gets sent to the modem. for a voice call the SoC proxies audio between the mic/speaker and the modem.