@lore If you have a spare STM32 blue or black, make it a Black Magic Probe. This is a proper way to use the board and it's incredibly capable. I keep a board flashed with it ready at all times.
https://github.com/blackmagic-debug/blackmagic/releases
https://hackaday.com/2016/12/02/black-magic-probe-the-best-arm-jtag-debugger/
So this is definitely worth putting on one of these MCU boards.