Resolution can't be changed, there may be an alternative way:
If icon looks too large (or small) on your screen try
- Reboot and stop at "Resident/Guest Mode" Menu
- press "Tab"
- press "Space"
- press "DPI=300" (if you want to have larger icon, otherwise try a small number)
- press "Enter"
After bootup, you should have a larger interface layout :)