The honest thing to say is psgroove isn't our problem.
The nice thing to say is that Apple's own emergency disk mode is untouched by Rockbox and still accessible to you. I don't recall the key sequence for the Mini, but google knows.
Or you could just reboot to the original firmware, and that is covered in our manual.
EDIT: psgroove (not ours) mucks with USB, so for all I know breaking mounting as a mass storage device might be par for the course.