Most Just Add Power devices will not allow an incompatible firmware to be loaded onto them. Unfortunately, the wallplate devices - 717WP2 and 718WP4 - are close enough that their firmware files can be loaded on each other.
If you find yourself in the unfortunate position of loading the 4-gang Wallplate Transmitter firmware onto a 2-gang Wallplate Transmitter, the 2-gang Wallplate Transmitter will not function appropriately.
To return the 2-gang Wallplate Transmitter to a functional state, apply this command through a telnet session to the Transmitter
astparam w board_revision;astparam w v_loopback_type 1;astparam w v_rx_drv_option 0;astparam w edid_rom_mode HDMI;astparam save ro;sleep 1;reboot