@
[email protected] It will fully support using other operating systems including users making their own builds of GrapheneOS. It's part of our hardware requirements. We'll likely be able to make hardened builds of firmware and drivers which can be released in an official way for easy builds without needing to extract anything from the GrapheneOS or Motorola OS factory images.
I think they’re pretty open? Atleast I’ve seen a few good custom roms for Sony Phones, like DivestOS (before it died). I don’t know if they stopped doing that recently.