Okay, so there's some misunderstanding between us here. If your factory "working" configuration with code 0xfe010001 works, then why didn't the box work after a fresh installation, without any external configuration file? Because the remote control configuration linked from GitHub is part of my Generic_S912 image by default, and if there is no external remote.conf, it will be loaded automatically. (You can find this file on your own box here: /etc/amremote/remote.conf.)
I always ran earlier builds of kszaq or wrxtasy LE 8.2.5 on these old boxes, and had a habit of adding a remote.conf file before trying a remote. I had no idea that your builds have remote files built-in.
After reading your last message, I deleted my 'modded' conf file from the SD card and rebooted the LibreElec, and what you know: factory remote worked (including ok button) without needing an external remote.conf file.
I guess I was being too smart to add a remote.conf file before trying a remote without an external remote file .