Without this flag, tools like Alex Page's USB Image Tool won't see drives exposed over USB Gadget as removable, and won't allow access to them. http://www.alexpage.de/usb-image-tool/ The code was pulled from the main-line kernel: drivers/usb/gadget/function/f_mass_storage.c Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>