Parameter IDs within a version 1 feature are often private to a particular feature GUID. The first feature in an AFU at the AFU's MMIO offset 0 has a unique problem: the GUID of the feature is the AFU's GUID. When an AFU feature parameter must be interpreted by the system, globally defined parameter IDs are needed. The following parameter IDs are valid for any AFU feature and should not be used for other meanings within an AFU:
| Parameter Name | ID | Version |
|---|---|---|
| MSI-X | 1 | 0 |
| Child AFU GUID list | 2 | 0 |
| Reserved | 3 - 0xff |