Motorola has committed to 7 years of support for the 2026 variants of the devices which will provide GrapheneOS support in 2027. There's still a lot of work to do in order to meet the GrapheneOS hardware requirements and there isn't going to be support for the existing devices. The whole point is they're working with us to improve their updates and hardware-based security features so that all our requirements are met. The stock OS is also a different thing than the official GrapheneOS support where we'll be making builds with their help. We'll be continuing to provide security preview patches and intend to move to newer kernel LTS branches than Qualcomm if they don't do it themselves.
GrapheneOS won't have to use their stock OS to get firmware, etc. as we do for Pixels.