2.1 Device Status Field reads in part:

*****
The driver MUST update the Device Status field in the order below to indicate its progress.
*****

The antecedent of "its" is unclear.

I am assuming "its progress" refers to the Device and not the driver. But as written, it could be either one.

If Device, suggest: "A driver MUST update the Device Status field to indicate the state of its device."

Reasoning that a Device Status field belongs to a particular device and that is the field that should be updated.

BTW, I said "A driver" because we are talking about any driver and not some driver in particular.