I wonder what the privacy implications are of having a remotely-updatable module inside every phone. Can carriers break encryption this way? Or otherwise snoop on users?
Yes they can snoop on the users, but they can do that now, without any changes to the radio firmware on the phone. The modem can't really do anything without the carrier's network.
If you mean spying on users by surreptitiously turning on the microphone, that's something where you want to control the phone's application processor rather than the modem firmware. Mostly because modern phone architectures have the microphones connected to the app processor instead of directly to the modem as in the feature-phone days (like a few years ago). Modern phones have sophisticated echo and noise reduction and use multiple microphones for that. And the audio is now used for other applications (like Skype or video recording) so it makes sense to hook up the microphones to the app processor instead.
Yes they can snoop on the users, but they can do that now, without any changes to the radio firmware on the phone. The modem can't really do anything without the carrier's network.
If you mean spying on users by surreptitiously turning on the microphone, that's something where you want to control the phone's application processor rather than the modem firmware. Mostly because modern phone architectures have the microphones connected to the app processor instead of directly to the modem as in the feature-phone days (like a few years ago). Modern phones have sophisticated echo and noise reduction and use multiple microphones for that. And the audio is now used for other applications (like Skype or video recording) so it makes sense to hook up the microphones to the app processor instead.