euh...
the latest Minix firmware (kitkat) with the bootloader taken from finless firmware : minix_x8_x8plus_x8_h_newbootloader_FW9
tested ok and by the way no need to rename anymore "boot_autoscript" to "boot.scr" to be able to boot from SD.
rebuilding a 18.1 image......
Flashed X8-H with Darth's FW
Using a fresh image 'LibreELEC-X8-X8H.arm-9.0-devel-20190202105130-8798984' Kodi 18
I can confirm power off is working with either the Minix remote or the power button (bundled Minix IR remote)
From what I can tell the Minix completely powers off (i.e. not standby) and requires the power button to power back on (i.e. not the remote).
Happy with that arrangement
Happy to test the next Kodi 18.1 IMG when released
Thanks to Darth all the hard work and Klaver7 for recommending the img