Attention is currently required from: Nick Vaccaro, Vladimir Serbinenko, Yu-Ping Wu.
Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/81508?usp=email )
Change subject: Support for creating hybrid vboot images ......................................................................
Patch Set 5:
(1 comment)
Patchset:
PS5:
I disagree about lack of value of using updates. […]
The problem with trying to reuse the updates ChromeOS ships is not with where you switch for dual-booting, but with incompatibilites between vastly different coreboot versions. This goes back to the comments I made in CB:81505, that your solution of trying to get ToT coreboot to work fine with an older RW just doesn't scale. Yes, maybe you debugged this for Volteer and tested and prodded around enough until you got it kinda working, but that doesn't mean it will work for any other board and it doesn't mean it will keep working for Volteer.
So if you really insist on having a firmware that can run the official ChromeOS firmware updates and can also dual-boot into Windows, then again, I think the right solution for that is to take the ChromeOS firmware-volteer branch of coreboot and implement you Windows dual-booting stuff on top of that. But you can't really do it with coreboot ToT, and I don't think coreboot should take patches that try to do that because it's going to be incredibly brittle and it's only going to work on the handful of boards that people have time to debug it on and it's gonna stick us with a ton of extra code and cruft just to maintain backwards-compatibility to things that were removed or changed for good reason. There's a reason ChromeOS is cutting a firmware branch for every board rather than trying to ship RW updates from coreboot ToT to all of them, because keeping things in sync across the RO/RW interface just doesn't really work.
That's why I'm trying to suggest alternative solutions that don't require reusing the official ChromeOS firmware update, because then you can have your whole firmware built from ToT and have a solution that actually works reliably across all boards and will continue to work as more development happens in coreboot.