I am fresh new here and just found this thread googling the device in the link here ->
http://item.taobao.com/item.htm?id=5122013945
In this page, it mentioned there existed an "E-BOOK upgrade package" to solve some common BUGs listed below. Unpack the package to SD card and restart, it will upgrade automatically.
1. WIFI incompatability with some brands of routers
2. Issues of "upside down" caused by incompatability of unofficial soft with the OS
3. Issues of "not showing 2G memory" when connected to computer (Some taken by system, actually showing 1.5G or so) -
don't know what this means
However there is no direct link to the upgrade. You will have to contact their customer service to get the download.