FWIW, I haven't done a lot of reverse engineering but I have written code to drive the USB peripherals for a few microcontrollers in the ST and NXP series and t

FWIW, I haven't done a lot of reverse engineering but I have written code to drive the USB peripherals for a few microcontrollers in the ST and NXP series and the techniques discussed in the article are just as applicable when trying to debug what the heck is going on in your USB code. I always get something interesting out of them.