webusb - Can WebUSB transfer files to a USB mass storage device, or act like dd?

Question

I'd like to use WebUSB to read and write files to a flash drive, or better, write arbitrary bits like unix's dd. Is this possible, or is only serial-like communication supported?

Answer 1

It cannot. USB mass storage devices are claimed by the system's generic USB mass storage class driver and are therefore unavailable to the browser.