quoted

It sounds to me like the best solution would be change the firmware
to lift that restriction and simply allow all IDs, in case it's not
actually a hardware limitation (which sounds unlikely).

Yes, that would be best but they told us, that it's not possible with
the available hardware resources. Subhasish?

Yes, In case if we allow the ALL implementation, it hogs the CPU.
In that case we do not need the PRU. The whole purpose of the PRU
is to offload the processor for any such implementations.