>We unfortunately cannot provide free baseband modem firmware, as there is no option available on the market which would be able to fulfil this requirement. Even if it existed, it would bring very little value to the users, as operating a radio device with modified firmware on public networks without recertification is prohibited in most jurisdictions of the world and privacy concerns in cellular networks are mostly related to what happens on the network side, not inside the device.
I don't have any more information than this. If someone can quote specific FCC regulations to back this up, I would find that very interesting :)