armbian refuses to auto run script.sh

[tung]

hello, i just installed Armbian for Odroid C2.

i have a simple script located at /home/tung/pixx.sh

the script is "feh --quiet --fullscreen --borderless --hide-pointer --randomize --slideshow-delay 30 /media/odroid/38C1-602E/*"

so it just opens my usb drive and starts a slideshow. nothing fancy.

 

i have tried rc.local and cron as seen here but my script refuses to auto run when i boot up  https://linuxtechlab.com/executing-commands-scripts-at-reboot/

if i manually type in terminal:  sh /home/tung/pixx.sh      then it works!

i have same issue with Ubuntu Mate and Diet OS. so at least i am consistent with my mistakes  :-D

please advise.