> Taken to school yet again.

We already talked about PCI keying there (with focus on 64-bit PCI back then, but 32-bit PCI is the same in principle):

https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=8334&forum=11&start=7
https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=8334&forum=11&start=15