One of these drives has a little switch inside
which allows you to
use the drive either as an RL01 or as an RL02!
That's an unofficial mod that is reasonably common. Basically, the switch
changes the link settings on the logic and DC servo boards to make the
drive behave as an RL01.
Watch out, though. The RL02 heads write a narrower track than the RL01
heads, and if you write to an RL01 pack in your drive, it's possible that
a real RL01 won't be able to read it. Reading RL01 packs is safe, though.
The DEC FS guy that showed me a drive that he had mod-ed also mentioned
that the same set of switches he flipped, also included a "force write
protect" to prevent accidental writing of RL02-width tracks on an RL01
pack. Seems prudent. It no doubt paralleled the switch on the front panel.
Disclaimer: I have never installed this mod on any DEC drive, but it sounds
pretty safe. YMMV.
-ethan