Dwight Madina

Without any logs, it is difficult to understand which issue you're facing, because it should work as is ...

Mini tutorial
I am putting here some notes for posterity
In the current version of armbian (testing H6) I use X11 / Xorg only reaches 1024x768, but my display reaches 1440x900.
To add this new resolution to the list of Settings/Display you have to give these commands:
 
# xrandr --listmonitors
(this command serves to see what it's called, the hdmi output)
 
# cvt 1440 900
(output: 
# 1440x900 59.89 Hz (CVT 1.30MA) hsync: 55.93 kHz; pclk: 106.50 MHz
Modeline "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 934 -hsync +vsync )
 
# xrandr --newmode "1440x900_60.00" 106.50 1440 1528 1672 1904 900 903 909 934 -hsync +vsync
 
# xrandr --addmode HDMI-1 1440x900_60.00
 
# xrandr --output HDMI-1 --mode 1440x900_60.00
 
If it works then modify Xorg with:
 
# sudo mcedit /etc/X11/xorg.conf.d/40-monitor.conf
 
Section "Monitor"
Identifier "HDMI-1"
Modeline "1440x900_60.00" 106.50 1440 1528 1672 1904 900 903 909 934 -hsync +vsync
Option "PreferredMode" "1440x900"
EndSection
 
# reboot