Posted on December 07, 2014 at 15:35Found my problem! The heap was too small (0x0200). After I increased it, everything started working.

Posted on December 07, 2014 at 14:03I ran into the same problem with STM32F407VG. Disabling the low power mode helped me a bit too. The COM port is now registered, but the device manager is reporting ''{Operation Failed} The requested operation was ...