Apple IIc External Drive: PR#7 Can‘t Boot

Attempted to boot external disk drive PR#7. No boot action and the words "AppleTalk Offline" appear at the bottom of the screen.
You may have a logic board which has ROMs compatible with the UniDisk 3.5 installed. Using PR#7 to boot the external drive is a feature which was discontinued in these ROMs to make room for other new features.

If you are using a UniDisk 3.5 use PR#5 instead of PR#7. If you are using any other drive, you can not boot from the external
drive.
Published Date: Feb 19, 2012