Change resolution via uart

I have monitor with max resolution 1600x900. I don’t see android screen because it used 1080p by default. How I can change resolution without any other monitor using only uart? How I can make it as default settings?
I tryed to make
$ cd /sys/class/display
$ echo 1600x900p60hz > mode
but it doesn’t work.

It still don’t support for the 1600x900 resolution output.
We are applying the documentation from Amlogic.
About more informations for it,you can look the post.