I apologize for not being clear.
When the depth was set as 24, the graphics looked like solarized and still no UI showed up.
Then I set the depth as 16 and connected a mouse through USB Hosting. When I right click, I can see 4 buttons "Volume Up", "Volume Down", "Home" and sorry i forgot one more button's text. When I clicked Volume Up button, I was able to see a dialog with volume slider but this dialog was cropped and displayed beyond the resolution. I presume the resolution has not fixed for 480x800. I will post some pics on this later.
Need some more time for me to know about X Window system / Composite Window Manager. Info#1 Info#2