building the firmware on OS X

This is pretty straightforward - first, download and install GNU Tools for ARM.  I put them in /usr and set the path in .bash_profile like so:

export PATH=$PATH:/usr/gcc-arm-none-eabi-4_7-2012q4/bin

then, simply cd to crazyflie-firmware and make cload.  It should build and result in something like:


Build 2:aba6937b9dab () CLEAN
   text   data    bss    dec    hex filename
  79620    460  16344  96424  178a8 cflie.elf

Note that "cload" will make a version of the copter firmware that can be updated using the Crazyload radio bootloader (for example, via the crazyload.py script).