from the peanut gallery of packagers:
first, please issue an actual release - with 100% working meson support including every feature the previous system has (cross) - full docs on how to use it
ask packagers to update. given them 3 months at least.
fix any problems that arise, including "i used to be able to do X by calling with Y" leading to adding a way to do X. After fixing them release a new micro with the fix.
only after everybody has been able to update, is it ok to drop the previous support from the master/main/whatever branch, leading to the next release not having it. If it takes longer until the new system is good enough, that's ok. It is not reasonable to set a hard timetable because that leads to dropping the old system before the new one meets requirements.
I have generally (not flashrom) seen a pattern of
we don't like automake
shiny system X is better
add X, release it
it works in the linux/x86_64 do-normal-things happy path
there are issues with other systems, cross or something
the previous system is dropped anyway
It's not always like this, but its often enough to make comments like this email!