Well, it was clear from the beginning that CNSD-310FM would take away NAV VR. If you backed-up /USER before updating your "real" Z130, it would be possible but dangerous. You'd be in a situation similar to -> http://avic411.com/index.php?/topic/36688-no-applicable-program-help/&do=findComment&comment=266583
Read the whole thread...it's not that long. But he was able to restore his unit (from a backup) to version 2 (Z120), then install CNSD210FM which updated everything (system, programs, data) to version 3.x (Z130).
Without a backup, it would be even trickier for you. If you plan to attempt this - BACKUP /USER to SD first. That way you've got a chance of repairing any damage that you do.
I can't give you step-by step instructions. I've never done it.