Hi tkocou, would you share your ugly baby script ? I'm interested too !
Thanks
Update:
Two issues:
First: As far as the "relatime vs noatime" issue goes, using a vfat format on the external HDD sidesteps the issue since vfat does not support either relatime or noatime options.
Second: The delay, between "playing" a video from an external HDD and the video actually playing, has gotten worse since implementing my fix. After observing the behavior, I've come to the conclusion that LibreElec copies the video from the HDD to the SDcard and then plays the video from the SDcard. This degradation occurs whether I play a video file located on an external HDD or when I play a streaming video from a source like Netflix or Amazon Prime.
Fixing the degradation issue will require upgrading the hardware (Raspberry Pi 4, etc.) and fixing the RPI firmware to boot from an external HDD thereby avoiding the use of an SDcard. The only potential problem will be how to get LibreElec to honor booting up from an external USB option (now available for the Version 4). Perhaps a dual boot with RaspberryOS and LibreElec.