Workaround for CoreELEC 19.x-Matrix green screen error when TV switched on after the tv box.

autostart.sh

#!/bin/sh

# Workaround for CoreELEC 19.x-Matrix green screen error when TV switched on
# after the tv box.
#
# Tested on:
#   - X96 Max+ (CoreELEC 19.0, 19.1 rc1/rc2)
#
# Original idea from user dasdreHmomenT on
# https://discourse.coreelec.org/t/matrix-wrong-output-mode-set-on-boot/15142
#
# File location: ~/.config/autostart.sh


display_mode_file="/sys/class/display/mode"
original_value=$(cat "$display_mode_file")

temp_value1="720p50hz"
temp_value2="720p60hz"

if [ "$original_value" = "$temp_value1" ]; then
    echo "$temp_value2" > "$display_mode_file"
else
    echo "$temp_value1" > "$display_mode_file"
fi

echo "$original_value" > "$display_mode_file"