it's seem like we read the same forums
the artatech representative on that forum said that trademark isn't onyx but inkbook. he doesn't answer straight who is responsible for manufacturing this peace of hardware.
But as someone noticed here, on their webpage they marketing this device as inbook Onyx
it's very likely that they used word onyx because their introduced this trademark in Poland so they dont want to start from zero to marketing new device. This device has so many similarities to Boyue so it's probably from boyue factory. I asked him what's origin of this device? So we should wait for answer.