See page 6 of the errata. this very entry was reworded.
Examples of what they mean:
Scenario 1: You're hacking a drone which, for whatever reason, isn't part of a PAN.
Drone rolls Pilot in place of any attribute, and rolls matrix attributes as relevant. Note, a drone's ASDF attributes are normally going to be 0s.
Scenario 2: You're hacking a drone which is sensibly part of a PAN for protection.
The PAN's owner (or Host's Spider, if the drone is slaved to a Host) can sub in their mental attributes as necessary, if they're better than the Pilot rating. And of course the ASDF values of the PAN master device(s) are invoked rather than the drone's own nonexistant values.