There is no scrolling in Actions list, so some upper buttons are not available on devices with landscape-only screens with low resolution.
For example: screenshot from the Car Media System (screen size is 6,2", resolution is 800x480, density is ...
Does this system have any hidden menus?
Yes, it has many hidden menus. You can install "More Shortrcuts" app from Google Play (or another similar app) and create shortcuts for hidden menus on your desktop.
I found a serious bug in UMI X2 (firmware 20130625 by UMI).
External SD-card is mounted as /storage/sdcard0 (and following symlinks /mnt/sdcard and /sdcard).
Internal storage is mounted as as /storage/sdcard1 (and following symlink /mnt/sdcard2...