To the OP / all:
Shutting down any µcontroller (especially the ST ones with their SWIM concept) in an undefined fashion i.e. by pulling the power is never a good idea.
Therefor I would think there is a (slim) chance of datacorruption when that happens.
So, I would try to reflash the controller - either with the original firmware, or the open source firmware.
You will find all the info on how to do both ways on this forum.
If you can not find it: @Elinx seems to have the magic overview of where to find what