I have a similar issue to :
https://community.st.com/s/question/0D50X00009XkgerSAB/stlinkv2-vcp-115200?t=1576249391369
When writing to the virtual com port from OS X Mojave, if I send too much data, the USB port hangs to the point that the one cannot kill the OS X process. The only way to recover is to unplug the USB cable.
The only "fix" is to insert a delay between characters. There appears to be an issue with the VCOM implementation.
The target board is an stm32f303RE nucleo board. I've upgraded to the latest stlink-v2 binary.
The target firmware is a simple Chibios program that echos characters. In any case, there is nothing this firmware could do to cause a USB hang -- even if it ignored the characters and sent nothing.
