I have an original Z1 upgraded to a Z3. The gracenote says to apply the firmware update to a Z3 only. Anyone know if I should try use the firmware update? Says it could damage the Z1 and Z2 units so I'm not sure. Thanks

a Z1 or Z2 upgraded to Z3, becomes a Z3, there's no difference to a unit that started out as a Z3. So you can use any software meant for the Z3.