Hi Helge,
ugh, that is an annoying side effect that I hadn't considered... sorry.
In the generated var/aircrafts/ACNAME/Makefile.ac you can see that the board makefile is included before the makefile variable is set.
@gautierhattenberger, what do you think about changing the generator to put _all_ configure (makefile variables) at the beginning of a target and not only the ones that are nested directly under firmware or target?
We shouldn't really have any configure options that are used more than once (where you would want to change them between subsystems...