I have a Multiplus II 12/3000/120 that was working fine. It is connected to a Cerbo GX. I updated Firmware via VRM and adjusted the charger settings for my lithium batteries. Since doing that, the inverter does not come on. It charges fine but when I cut shore power, the inverter does not come on. I have 13 volts at the inverter terminals. I have the toggle in the "inverter and charger on" position. I have it set to "on" via the Cerbo. But when I cut shore power, it just shuts down completely: no lights on the unit or anything. Help much appreciated.