What if I stored data in my mouse

A developer explores storing data in a Logitech MX Vertical mouse by reverse engineering the HID++ protocol. After writing a Rust tool to enumerate the mouse's 33 features, they discover that macOS silently blocks certain HID++ write operations, the device name register ignores writes, but the DPI register accepts arbitrary u16 values with no validation. The result: 2 bytes of persistent cross-computer storage encoded in the DPI register. The post reflects on the value of exploratory, low-level hardware hacking as a learning exercise rather than for practical utility.