Back in May of this year, Adafruit released the TinyUSB stack for the Arduino IDE, which supports SAM D21, SAM D51, nRF52840, and STM324F-based development boards, such as Adafuit’s Feather M4 Express. The TinyUSB library allows those boards to appear as a USB drive, letting users drag-and-drop files directly to the board, much in the same fashion as a flash drive. Configuration files, images, audio, fonts, etc., can all be imported through a few clicks of a mouse. What’s more, the TinyUSB library can be implemented to take advantage of SPI Flash, SD cards, and internal chip memory as storage options as well.
The release of WebUSB provides users with access to those storage options securely over the internet using compatible browsers. Adafruit explains:
It’s unknown if Google has patched this security flaw for their Chrome browser in the latest revisions. That being said, Adafruit has uploaded WebUSB example code, and webpage code for the TinyUSB to their GitHub repository for those interested.