Why is use strict; commented?!

Your script only works when the current directory is the same as the one passed to find and when no matching files are found in subdirectories. Some of the instances of $_ should be $File::Find::name.

If you don't care to search subdirs, File::Glob's bsdglob might be more useful than File::Find.

Why do you do a second find? Either there weren't any USB file to begin with, in which case you already know all the USB files since you just created them, or you are clobbering some USB files while leaving others behind (which doesn't sound correct).

You're doing a case-sensitive match on a case-insensitive file system. The "i" modifier should be used on your match operators.