When trying to use ASC or CAN bootstrap for flash programming on STM32 targets I have no success.


  • Check pins BOOT[1:0] = 01 for enabled boot from system memory.
  • Check if your target is affected by errata 2.13 and do the required settings (see STM32F105xx and STM32F107xx Errata sheet).
  • If that target is connected via USB and the device is recognized by the host PC it is possible that the DFU gets activated instead of ASC/CAN boot loader. In that case you either have to disconnect USB or make sure that USB is not recognized by host PC, e.g. by pulling PA11 or PA12 to ground.
  • When using STM3220g-EVAL board make sure that J31 is open to prevent pin PB11 getting Low. When using CAN bootstrap loader make sure J3 and J10 are set properly to CAN2.