If I buy such a tinkerphone as this, I want to be able to play with it at all levels. For example: Imagine the mobile connection doesn't work, but it still displays the GSM network's name? So it still transmits some data.... I want to be able to see where it hangs. E.g. do my packets reach the other station? Do I get garbled responses, or no responses at all? ... I want to be able to access the audio stream programmatically, which is not possible on 99% of android phones. And so on.
Mobile technology is such a black box, due to closed firmware. I wonder what amazing things will be possible if people can hack their phones' radios.
(* With focus on "I can compile and modify everything myself", don't care too much about license politics.)