Question

I've uploaded and installed driver bundle 1.3.5 and 1.3.8... installed manually, and through the regular installation process.

I've tried reinstalling several times... I'm at a loss.

Answer 1

You'll need to downgrade the firmware to an earlier version to make it work with the older version of Logic Pro. 

http://support.presonus.com/entries/21335709-Faderport-1-2-installer