# ZX0 bootloader This is an I2C based bootloader for the SAMD21. It implements the [Microsoft HF2][hf2] protocol over I2C and uses the same double-tap-for-bootloader and magic as the Adafruit UF2 bootloader. The bootloader is written in C++ and uses Zephyr for the drivers. It should be easy to adapt to the SAMD51 and other devices supported by Zephyr but each will need a custom I2C client driver. -- Michael Hope [hf2]: https://github.com/microsoft/uf2/blob/master/hf2.md