So, Payload data is stored in a system file (hopefully present in your backup). To be able to load those kind of files, you need to be in CTRL Start mode.
To access with the Tablet TP: Menu->Utility->Cycle Power and there you can select which start mode you want the controller to use at the next power cycle.
You then need to manually cycle the power.
Once your files are restored, make a COLD Start, press FCTN on the TP keypad, choose Start (COLD) and the controller will reboot.