1)Download Rockchip Batch Tools v1.5. Download firmware as needed.
links : http://www.mediafire.com/download.php?koja23446mrl6zb or http://www.arctablet.com/blog/archos-tablet/flashing-your-rockchip-3066-based-tablet-rockchip-batch-tool-1-5/
2) Open your UG802 (gently) with a plastic opening tool (used for mobile repair) or guitar pick. (do not to break clips)
3) Locate your NAND chip and the 2 pads next to it
4)Short the pads while plugging the UG802 into your computer. Windows >>> detect a new device.
5) Under control panel –> device manager, right click on unknown device, and choose update driver. Install the windows drivers located in the Rockchip Batch Tool folder. Should see “RK30sdk” device.
6)In Rockchip Batch Tool v1.5 . Select firmware image “xxxxxx.img” and choose “Restore”.
7)If successful “Restore Done Success<1> Fail<0>“. You are done
IMPORTANT: The method may break/destroy your UG802′s device. I am not responsible if you hurt yourself or your device.