This version of contiki adds support for the stm32f4 mcu and my stm32-bv motes.
You can read about the hardware and get all the design files here:
http://vedder.se/2013/04/cc2520-and-stm32-rf-boards/
I have also documented how I made this port and how to use it. You can read about it here:
http://vedder.se/2013/10/a-contiki-port-for-my-custom-cc2520stm32f4-boards/