Note: This does a WIPE upgrade so make sure you have anything backed up before you do this! After this the tablet will be as it was when you received it except on a later firmware.
1. Download the latest firmware (see this link)
2. Within the firmware there is a Rockchip batch tool but this is in Chinese so use http://www.mediafire.com/download.php?wcx3cjejjo707rm
3. Extract the Rockchip batch tool which includes the necessary drivers for Windows
4. Run the RKBatchTool_1.5.exe in the extracted Flashtool folder and select the image you downloaded from Cube
5. Shut down your tablet
6. Plug the USB cable into your tablet
7. Now pressing the power and volume + buttons together connect the other end of the USB cable to your PC
8. Once Windows notices a new device release the 2 buttons
9. When asked for drivers browse to the “drivers” folder within the extracted batch tool folder and select it allowing windows to install the driver. If you aren't asked for drivers and you get a device install failure go to Device Manager and look for Unknown Device. Right click on this and select update drivers. Browse to the folder within the RKBatchTool folder with the drivers for your OS (Win 7 64 bit in my case) and select this folder.
10. If all ok the "device 1 connected" square within the RKBatchTool_1.5 will change from grey to green
11. Press the “upgrade” button in RKBatchTool_1.5
12. The green square should change to orange showing that the flash operation is happening
13. If all ok you should get a success message at the end (takes about 3 minutes)
14. The tablet should reboot but if it does not then press the power button
15. The first boot after an upgrade takes much longer than a normal boot. Just be patient and wait for the lockscreen.
16. The default language will be Chinese. When you get a prompt hit the home button and then go to settings and look for the menu option with a letter A in a white box (this is language). Select this and then the top option on the right hand side of the screen. This will give you a list of languages. Select English (UK) or whatever and then restart the tablet.
17. Don't forget to click green + bottom right of this post if this has helped you.
v1.0 Initial untested version
V1.1 Updated following testing
v1.2 Updated to show that this is untested on the Cube U30GT-H model. Added change history.
v1.3 Updated to show that these instructions work on the Cube U30GT-H model (Thanks Krikkit)
NOTE: I take no responsibility for you updating your device. You do so at your own risk. Please use the tablet’s own update feature if available as this is a lot safer.
Edited by Jezzer, 10 September 2012 - 04:40 AM.