Building instructions. In order to build your applications you need to find out the right cpu revision for the board you are using. Valid STM32W_CPUREV values are CC or xB Examples: The MB851RevD board has a cpu with code stm32w 108CCU7 so CC is your STM32W_CPUREV value and the command is make TARGET=mbxxx STM32W_CPUREV=CC ... or The MB851RevC board has a cpu with code stm32w 108CBU6 so xB is your STM32W_CPUREV value. make TARGET=mbxxx STM32W_CPUREV=xB ... NOTE: if the last word is B you need to use x as wildcard.