According to this thread(http://forums.leaflabs.com/topic.php?id=10456 ),Latest development effort for libmaple which support STM32F4 is going here. https://github.com/AeroQuad/AeroQuad/tree/development/Libmaple. On below link, @yamanekko Already succeeded to run mruby on STM32F4Discovery. https://github.com/yamanekko/mruby-on-stm32f4discovery/wiki/build-mruby
According to this thread(http://forums.leaflabs.com/topic.php?id=10456 ),Latest development effort for libmaple which support STM32F4 is going here.
https://github.com/AeroQuad/AeroQuad/tree/development/Libmaple.
On below link, @yamanekko Already succeeded to run mruby on STM32F4Discovery.
https://github.com/yamanekko/mruby-on-stm32f4discovery/wiki/build-mruby