Comment # 1 on bug 1066682 from Daniel Molkentin

From a dracut perspective, this "works as intended":

add_* variables add to the default/existing ones, the others completely
override it. since there is no add_ version for fw_dir, you would need to
prepend all default pathes as a workaround.

However, in this case the include file seems broken. Whoever did that wanted to
hardcode a particular kernel version, which looks wrong. If there is indeed a
good use case for this, we can still take adding an add_fw_dir to upstream.

Maybe sndirsch can help to shed some light on this?