The following will only work if you are using LibreELEC 8.0 (or at least some beta 7.95.x)
Please do us a favour and revert all the changes you have done to dump the custom EDID. It might be that you might have done something wrong. I've written a script which does all the steps for you by entering a single command. But that script will fail if you have already made changes to specific files which are involved to this task. So please revert all the changes you have done. After that SSH in and run the following comman:
Make sure everything will work before you enter that command. You shoild have a screen and working audio. If that doesn't work before, the EDID might be faulty and won't work.
Note: the getedid-script is not part of LibreELEC 7.0.3. If you are using that, the command above doesnt work.