As long as your network traffic is sanitary before it hits the baseband (Tor, VPN, or something you trust) you're good on that end. A better design would be to

As long as your network traffic is sanitary before it hits the baseband (Tor, VPN, or something you trust) you're good on that end. A better design would be to have three settings for the mic: baseband, app processor, killed, so you could run the audio path through free software as well (VoIP). The idea is to minimize what the baseband is doing in the system, and assume it's malicious. It's hard to duplicate PhD person years on the signal processing side, and, if you get that far, then navigate the IP minefield.