They want to differentiate software and hardware. When user is not supposed to install the software at all, they threat such device as "a circuit" and not as a general purpose computing device.

I understand it as an attempt to draw a line somewhere on where the software ends and the hardware starts. Not very successful one IMO and I think our project is a good example where it doesn't apply very well.

However, there's also a privacy aspect in their argumentation that they're embracing, and I don't understand at all how forbidding firmware updates is protecting anyone's privacy, since the backdoor may be there from the very beginning.

(BTW. "tivoization" will be there anyway unfortunately, as almost any GSM modem has signed firmware - those that don't are few generations old and there's still not a plenty of them...)