Hi,
as you already found, there are currently almost zero serious choice available for a really free mobile baseband. On the other hand we want to create a product which will be usable when shipped. Developing a mobile 3G or 4G baseband is not within the scope of our project since this would involve way too much effort.
What we aim at are two major points:
First we want to make sure that the 3G/4G modem is as separate as possible from the main CPU and RAM. Thus we can not and will not use chipsets which combine main processor + baseband in one - like Qualcom Snapdragon etc. The mode will be a separate part with defined electrical interfaces (like USB + UART) and no direct access to main CPU peripherals. We will also implement some form a hardware kill switch, i.e. a switch to disconnect the modem from the main system so that users can be sure that the modem is a) not powered anymore and b) there is not data flow from main processor to/from the modem.
Second we want to use a mode chipset which may in some future be freed. There are some already pretty well known and some reverse engineering has been done. Even if we can not provide a free baseband firmware we at least want to create a device which can eventually be turned into a completely freed device by upgrading the modem firmware to a free version.
I hope this helps a little. We will give updates once we have any news. And yes, we are also dependent on pointers from backers, users, interested people! We can not know everything. We try our best to do thorough research. But we are setting foot on pretty uncharted terrain. So any help is very welcome!
Cheers
nicole