Canaan firmware up to A9 is all open source.
BM firmware up to S9 is all open source.
Those only make a very small percentage of all the gears in the world, besides, the S9 as is, is an old obsolete model and mostly dead, the newer versions have different firmware which isn't open-source, so it's safe to say that the vast majority of OEM firmware is closed source, I know you like to make it seem like that isn't the case, just to justify allowing them to use your pool, but that's for a different topic.
except S9 bos before they changed it to closed source and charged a fee.
Wrong, BOs is fully open-source, BOs+ is not, those are two different firmware, perhaps you should do some reading before claiming things that are far from accurate.