http://www.s1fw.com/plus/search.php?...e=titlekeyword
http://www.s1fw.com/plus/search.php?...e=titlekeyword
Your flash is only 16Gbit = 2GB, so that is the real capacity.
If you can get it to function as USB drive, it means the firmware core and Udisk driver is already compatible. Now you just need to find appropriate driver for the display and keyboard, and build a firmware in that way.