[Milhouse]

Interesting. On my system editing /flash/syslinux.cfg had no effect But then again, I have not reinstalled Libreelec completely for many months, I just use the update function for the time being.

Right - because you have both /flash/EFI/BOOT/syslinux.cfg and /flash/syslinux.cfg. SYSLINUX will use the former by default, but is happy to use the latter when the former does not exist.

Since having two SYSLINUX boot configs is confusing, new installs (since 8.90.003/May 2018) will only install /flash/syslinux.cfg - I had thought we had applied this change for existing installs but obviously not.

To conform with the new "single config" approach, what you can do is move your /flash/EFI/BOOT/syslinux.cfg to /flash/syslinux.cfg (or just delete /flash/EFI/BOOT/syslinux.cfg if it's not been modified).