Rio 500 Killed by a Firmware Upgrade by iTunes on OS X


I just upgraded my Rio 500 for the latest .cnt file with iTunes on OS X. After the successful bla bla, i reboot my Rio and he allway say < USB Connect > and he doesn't mount anymore on the sources manager. Does anyone know how i can downgrade or reset my Rio 500 ?? Thank's Apple! :-(
Just download the newest firmware from, I think a new one was posted today.
The 'grey screen' symptom i have had on many an occasion, but is easily fixed with a new FWare UD.
The usual culprit is a low battery when transferring files or UDating the FW, but I've had it on a couple of other occasions.