bcdedit /sysstore This command sets the system store device. This command is only valid for EFI systems in cases where the ...

bcdedit /sysstore 

This command sets the system store device.  This command is only valid for EFI
systems in cases where the system store device is ambiguous.  This setting does
not persist across reboots.

        The name of a system partition to set as the the system
                    store device.  The device must be a system partition.

Example:

The following command sets the system store device as specified:

    bcdedit /sysstore C: