Impulse RC Driver Fixing Tool (for flight controller USB connection problems) (3 min 19 sec) In the comments below that video there are lots of people for whom the ImpulseRC Driver Fixer is endlessly searching for the FC. JB seems to indicate here: https://youtu.be/e7dGCZMJ6SA?...
When re-installing driver with Zadig or ImpluseRC driver fixer, it would show up as “STM32 BOOTLOADER” but would then it would always revert back to “Guillemot STM DFU Device”. To fix this you have to remove Guillemot first: