> This uses an STM32 microcontroller to act as a USB mass-storage device, serving up a dynamic file. This file can be loaded by the system's boot config to chan

> This uses an STM32 microcontroller to act as a USB mass-storage device, serving up a dynamic file. This file can be loaded by the system's boot config to change its boot behaviour based on the physical input pretty neat idea! An alternative might be to use a plain USB stick, put switch onto its power line, and check its presence in the grub.