New X3 camera on inspire 1 pro

You are correct in your summary.
 
yes spot on.. its like the phantom 3 pro and advance. the only difference in the firmware is the camera.. both firmwares contain the same data for the craft and batteries ect, the only difference is the camera.
so make sure you do all main updates to the craft with the pro firmware with the x5 camera on and only use the standard firmware to update the x3 camera only, with the x3 camera onboard of cause.. so you will only use the standard inspire 1 firmware to update the x3