When I started to develop the dragonCopter, I used Keil Realview MDK Evaluation (Code Size limited to 32KB) and some self-built Eclipse/Codesourcery solution which overcame the 32KB limit, but which did not work very well (especially debugging did not work well when it came to set breakpoints over Segger GDB Server). Since the project will grow out of the 32KB limit when it comes to navigation features, it was time to switch development tools to a free solution. I recently installed Coocox which is a very good eclipse based IDE for ARM Cortex Development. It works together with GCC ARM Embedded which is maintained by ARM developers and seems superior to the Codesourcery Toolchain. Coocox seems very nice, its only drawback so far seems that it is not yet ported to linux. But GCC ARM Embedded is ported to Linux, so development on Linux could be done with another IDE and makefiles for GCC ARM Embedded.