https://github.com/libopencm3/libopencm3/pull/471
https://github.com/libopencm3/libopencm3/pull/457
https://github.com/libopencm3/libopencm3/pull/534

https://github.com/libopencm3/libopencm3/issues/456
https://github.com/libopencm3/libopencm3/issues/455
https://github.com/libopencm3/libopencm3/issues/454