title_body: Can I re-flash the Hubsan fpv1 controller with built-in fpv screen?
upvoted_answer: I'll start by warning that you may have misconceptions that are leading you in the wrong direction. The reason that FPV screens built into transmitters are not more popular is that screens aren't bright enough to compete with sunlight. The primary function of goggles is to cut out bright reflections, so you can see the picture.
  Also, transmitters are comfortable when held down at your waist, which would make the picture on these transmitters too small. You'd need something the size of a laptop or tablet computer screen to work well at arms length. The picture from an FPV camera is pretty low quality by modern TV standards, and needs all the help it can get.
  The transmitters you link can't be flashed to run OpenTx. They just weren't designed to be modified like that. They may not even have enough flash memory or processing power, as OpenTx has vastly more features. Similarly Hubsan doesn't sell a stand-alone receiver for their transmitters.
  You probably could buy an OpenTx radio and transplant the electronics into one of these cases, but I think you'd have to find something clever to make their TV format screens display information that was designed for a dot-matrix screen. You could look at the boards used for OSD (On Screen Display) but I imagine it would get very technical.
  I think your best bet would be one of the many FPV monitors, mounted to the top of a normal transmitter - just be sure to stand in a shady spot.