Note. Most "generic" STM32F103 boards only have a reset button, and not a user / test button. So the bootloader code always configures the Button input pin as PullDown, hence if a button is not ...
While things like the Arduino platform certainly opened up the gates of microcontroller programming to a much wider audience, it can also be limiting in some ways. The Arduino IDE, for example, ...
Bootloader for STM32F103 boards, for use with the Arduino_STM32 repo and the Arduino IDE - AlanMake/STM32duino-bootloader ...