The cli fnsysctl cmd will allow you to read the proc filesystem devices. Here's a quick means for querying the usb-bus if you should run into problems with mounted devices.
( example query the bus on a FortiGate 100A )
( example query the bus on a FortiGate 100A w/8gig memory stick insert into a usb port )
NOTE: If you run into issues with connectivity over the USB ports, please user the cat command within the proc filesystem.
Freelance Network & Security Engineer
kfelix -a--t- socpuppets ---d--o--t--- com
=( ! ! )=