Have you ever used a Pandora in total darkness? Besides the screen being too bright even at its lowest brightness setting, the LEDs can be very annoying. Luckily I can, and I do, switch them off.(and can't help thinking that being annoyed by a LED is even more ridiculous)
This sounds excellent ! Trusting the Pyra and it's operating system we have full control over the modem chip.2. there is an external power FET switch (TPS22964CYZP) on the Pyra mainboard controlled through a gpio from the CPU. It can be turned on/off to cut power to the modem. So if you want to have it really off, do some "echo 0 >/sys/class/gpio/...".
It shares the same power supply and signal processor as 2/3/4G inside the module. So it is also powered down for sure if you disable the power switch FET.