Start:
1. boot
2. login: root
3. insert usb-flash and see:
# ugen4.3: <JetFlash> at usbus4
umass1: <JetFlash Mass Storage Device, class 0/0, rev.2.00/1.00, addr 3> on usbus4
umass1: SCSI over Bulk-Only; quirks = 0x0100
umass1:1:1:-1: Attached to scbus1
(probe0:umass-sim1:1:0:0): TEST UNIT...