Object code only modules date back to 2.2 and 2.4 kernel times, when
IBM did not release the source to certain kernel modules. Since many
years everything needed to boot and run the machine is actually
open source. It also got broken due to the kernel growing larger and
adding the oco.bin would overwrite parts of the kernel.
It's safe to say that nobody is actually using this.
Philipp Kern
Steve McIntyre