yea i thought it would be a silicon bug since the stm32f401 worked fine and they are basicy the same chip just with more ram, rom and kHz. i have 2 more stm32f411s and stm32f401s comming soon so i can test it on the other chips and just tripple cheack that its not that one mcu's silicon that is the issue. i also saw the #40 ticket and it deffinately does sound like they are haveing the same problem. if you want any help with testing stuff im more than happy to help out where i can. Maybe we could...
libusb_control_transfer returned -9 (LIBUSB_ERROR_PIPE) on STM32F411CEU6