Simple. Mer project has open roadmaps. Each HW port has one or more maintainers. Guides exist how to port Mer. I stick with Nokia HW port. Any HW port maintainers would be in touch with vendor if they are cooperative. If something comes up that I cannot personally handle, I pass it on to others who can. Each vendor / HW port is equal in terms of the Mer project and can see what is going on due to the roadmap. Some ports are more developed, some less.