You might also be interested in https://github.com/daniel-thompson/wasp-os https://github.com/daniel-thompson/wasp-os which runs on nRF52-based hardware (there

You might also be interested in https://github.com/daniel-thompson/wasp-os https://github.com/daniel-thompson/wasp-os which runs on nRF52-based hardware (there may be eInk-based variants as well)