HDMI output issue

[Nwest]

Hello!

I'm trying to get a Pi 5 up and running in my living room. Ideally, I want to use it for playing retro games, including Nintendo and ScummVM, streaming content from my gaming PC via Moonlight, and, if possible, also playing content via a browser, such as bvb.tv or YouTube. So that sounds like I am in the right place here.

I really want to play some retro games and adventure games with my daughter. I somehow have an educational mission to accomplish. I hope that I can find a way to get the Pi5 to run stable.

I have the following setup in my living room:

Pioneer VSX-1025 receiver with 5.1 speakers
Acer projector

I also use the receiver to transmit other content to the projector and distribute the sound to my speakers. This works excellently with my existing hardware (Chromecast stick and tv-satellite receiver), but unfortunately not with the Pi 5 and recalbox.

I have found the following workaround: I have to cold boot the projector, receiver, and Pi 5 simultaneously. However, if I switch HDMI inputs on the Pioneer receiver, nothing works. Only a simultaneous cold boot does the trick.

Even then, it only works about 50% of the time—I get picture and sound initially, but as soon as I start a game (under Recalbox), the resolution changes, and the receiver can no longer process the signal.

Under Raspberry Pi OS (64-bit), things are a bit more stable, but again, only with a simultaneous cold boot. At least with that setup, I managed to get the browser, ScummVM, and Steam Link running.

Now I wanted to upgrade my setup with Recalbox, but this reveals the weakness of my setup because I can't start any game without losing the signal.

I have opened a thread for this in the raspberry pi forum:
https://forums.raspberrypi.com/viewtopic.php?p=2292146#p2292146

The last answer in this thread led me to this place. I should consult Recalbox Support:
Since the author has no experience with Recalbox, they recommend asking the Recalbox team how they configure the display.

That's what I'm doing.

I should also Check EDID Data:
A good starting point is to check what EDID (Extended Display Identification Data) is being sent to the Raspberry Pi. This can be done using the command:

edid-decode /sys/class/drm/card1-HDMI-A-1/edid

Where/How can I check edid data when running recalbox? Where can I type this when I run recalbox? Is there a console?

I should force a Video Mode in Recalbox:
If the display does not work correctly, it may be necessary to force Recalbox to use a supported video mode. The Recalbox team should be consulted on how to do this.

Where exactly can I set these settings?

Due to my lack of understanding of EDID stuff and advanced HDMI mechanics I am seriously confused. Any help is appreciated.