Just upgraded my firmware successfully. So far so good. I know it's mentioned in this thread but I would suggest they change the name of setting 'voice' in SettingsMbox to 'audio'.
The mount points for my external hard disk had changed to I had to edit the sources in my XBMC after I had restored from my backup.
One other thing is my games R-Type and R-Type II are no longer compatible so I can't install them. It's not a big issue because I have a proper gaming desktop PC attached to my TV too for real gaming. Just interesting why certain apps are compatible with certain firmwares.
+1 to Geniatech (myGica) for not forgetting this box.