SW4STM32 - use GCC v4.9 ?
I would just second this question. Mbed clearly says not to use 5.4 which is installed with SW 1.14.0.
https://developer.mbed.org/forum/helloworld/topic/27833/
I don't know what the answer is, but mbed clearly has a system workbench export option, yet this is incompatible out of the box.