Documentation added by Riku, for 3 Libreboot board ports that Riku also added recently:

https://libreboot.org/docs/hardware/hp9470m.html

And these:

https://libreboot.org/docs/hardware/hp2570p.html

https://libreboot.org/docs/hardware/hp8300usdt.html

These boards will be present in the upcoming Libreboot release.

Thank you, @rikuv !