Historical retained-firmware guidance says that the old bus-probe algorithm enumerates KZPAA controllers before KZPCA controllers regardless of PCI position. In a two-controller example, that assigns PKA to KZPAA and PKB to KZPCA. The complete old/new comparison below was not independently executed during the 5.1.0 documentation review; confirm the actual names with SHOW DEVICE before changing any boot definition or guest configuration.

In a more elaborate example with three SCSI controllers, the maximum supported by Avanti:

The retained firmware provides the following historical sequence to request PCI bus order:

>>> set bus_probe_algorithm new
>>> init

After the initialization, verify the resulting controller and disk names at the console. Changing enumeration can change boot-device paths; make the change only with console access, a recorded copy of the previous settings, and a tested recovery path.

The historical restoration sequence is:

>>> set bus_probe_algorithm old
>>> init

Verify that the expected names return after restoration.