Solution found!I used two examples for my implementation. One of them disabled the USB OTG interrupts and called the interrupt functions in the main while(1) loop. The other used proper interrupts. Digging into my higher level USB handling I found th...

I have inherited a legacy STM32F407 project using STD libraries, bare-bones, no RTOS, usbd_core.c version V1.2.1.I am implementing a USB VCP interface. I am getting seemingly random hardfaults in USBD_SOF(). I start the debugger, USB is connected dir...