There are no secure smartphones
The folks at http://neo900.org/ are well aware of this and that phone is designed accordingly (details at http://neo900.org/faq#privacy). Hype-driven products like BlackPhone misrepresent their devices as being perfectly secure when this significant attack vector is completely unmitigated.On the Neo900, the modem is connected via USB (bus; there is no physical connector) which means it doesn't have DMA. There is no feasible open-source baseband. OsmocomBB (http://bb.osmocom.org/trac/) is the closest thing to one, and it is relatively incomplete and works on a very limited range of mostly badly outdated hardware, none of which would not really be reasonable to use in a phone to be manufactured today.It's incredibly difficult to get people to care and help with the lack of software for tasks like GSM communication. Somehow even among people who describe themselves as "hackers", most just want to run Android or iOS and buy/run closed-source apps, and are more interested in Javascript and employment than reverse-engineering and doing things that have never been done before. The potential of reprogrammable computers that, at a low level, run the code you ask them to doesn't seem to get through to most of the HN crowd.