My problem: after downloading firmware to the EZ-USB based device with ezdownload it doesn't appears back on usb bus. My solution: In file /usr/src/sys/dev/usb/usb.h there are lines: #if 0 /* These are the values from the spec. */ Changing from 0 to 1 does help me. Specifications rulez! :) Thanks to Bernd Walter! Our conversation on this topic helps me a lot.