I'm in the same boat.
When I got the van ('22 Limited Hybrid) in February, I was able to play a movie from a USB drive in the head unit, control both screens, mirror them, have the audio in the car speakers.
Now, it acts as if the head unit was unable to detect the rear screens. Turning the screens on/ off on the head unit does not change anything to the rear screen. Changing source does nothing, rear screen remains in FireTv input. Both screen previews in the head unit remain black. Mirroring screen 1 to screen 2 from the head unit results in the screen 2 preview correctly entering the mirror mode, but mirrors the black screen. The actual rear screens don't go in mirror mode.
Both screen previews are labeled screen 1 and screen 2, while they used to be labeled left and right screens.
HDMI input is no longer displayed in the source.
When I had it working, both the head unit and the rear screens never connected to a wifi or mobile network. I had not setup FireTV on the rear screens either as this required a wifi connection.
I starting having issues (different than the current issues, but was unable to play the video from front usb) after I set my cell phone as a wifi hotspot in order to complete the FireTV setup. I used the hot-spot only that time, running offline the rest of the time.
I gave up with the screens for a while. In the meantime my home router died and I replaced it with a mesh system, which brought my driveway within my home wifi range. It was outside the range with my previous router. This allowed the car to get an OTA update through wifi.
And now I have the current issues of the head unit and the rear screen apparently working independent from each other without talking to each other.
I'm a software engineer and what I think is this:
- prior to the '22 model with the FireTV this seemed to be more stable. I think the switch to FireTV broke the integration between the rear screens and the head unit. This integration appears to be still very buggy, and IMO a real piece of sh*t definitely not production-ready. The rear screens appear to work (just did a few very quick tests though) if used standalone, the issues really seem to be with the head unit integration.
- with the current version, the issues I have look as though for some reasons the head unit does not detect the rear screens, and use dummy virtual screens instead, hence the labeling change.
Since the issues arised for me after setting up the FireTv, has anyone tried to factory reset the rear units and then control from the front without setting up FireTV on the rear screens? With no wifi or network connection.
Since my model does not have a bluray player, i was considering a workaround for the lack of bluray player and these issues:
use a raspberry pi 4 as a media center. It would be powered by one of the usb ports. It has 2 hdmi outputs, so one for each screen.
I would set it to mirror the same display on both hdmi outputs: i have 2 young kids who would be watching the same thing.
I could have an external usb dvd drive connected to the raspberry pi.
I could connect audio through bluetooth if possible, or else through the aux port.
The raspberry pi could be remotely controlled by a phone or tablet
Not while driving of course, but my wife in the passenger seat could control it.
But if the front control was working properly, I could have a simpler solution.
Use the same old tablet, but without the raspberry pi. Connect the DVD drive in the tablet. Cast the tablet screen to one of the rear screens (start the cast from the head unit) and mirror to the other rear screen.
This requires the head unit control to work properly though