Well, I finally got LibreElec to boot on the Zero 3W. I don't even know how I did it, but I think installing Debian from Raxda's official website and updating it had a lot to do with it.
Maybe it wrote the bootloader to the eMMc or somewhere else on the board, and thanks to that, LibreElec could boot... I don't know, since I'm not familiar with that. But I'm convinced that updating Debian fixed something.
Well, I can finally test this motherboard with LibreElec and other operating systems to try things out. Just so you know, LibreElec runs very, very well with the 2GB RAM motherboard.
Now, the only thing left for me to try with LibreElec is to install it on the eMMc, which I don't know how to do.
I know I can install it from the LibreElec configuration add-on menu, but no matter how hard I try, it won't install. Even though the message "Installing on eMMc" appears, it disappears and doesn't do anything.
I would appreciate @balbes150's help in understanding the complete installation process on the eMMc.
Greetings, and once again, THANK YOU SO MUCH for all the work you do.