The players in my group stumbled across some old-as-hell-but-still-spaceworthy Delta-7 Aethersprite interceptors. They don't have hyperdrives and there's no Hyperspace Rings left in our GM's game fiction.
That "Hyperdrive Generator" is in the book as an attachment, and it reduces your hyperdrive rating by 1.
Rules as written, we don't really have rules to set up the Hyperdrive Generator (FDCRB page 258, I think), to ships without a Hyperdrive rating, do we?