CODE AND STORAGE OVERLAP while building firmware for NRF52

As for simple BLE implementation over gatttool, yes, everything is there, DFU procedure needs all basic features I guess and it works. pexpect python module makes it very easy, not sure what would be best in C for spawning process and pattern matching its output. So far gatttool just works when scripted like that however one peculiarity is that commands (like 'characteristics' that lists all of them) run asynchronously over prompt so it is a bit harder to match where the output ends as you get the prompt result [xxx][LE]> immediately and also each output line just overwrites the prompt so basically each line of output data is prefixed by prompt with some control and \r characters. So you cannot get all command output simply by waiting for next prompt and taking everything above it. So e.g. with 'characteristics' I simply have 3 seconds timeout to get the list and hope I got all of it. Other commands have specific string output pattern to match (receiving notification, MTU negotiation) so that is not an issue. Also you can miss something when waiting for two things - e.g. when pattern matching current command output and notification comes first instead. Anyway if there is easy pexpect like library for C it should be doable and not that hard.