Maybe this is a bit late, but hope this helps
Hello, I just repartitioned my Viva H8 tablet.
So I had this around (the recovery image): 4shared.com/file/23KWsUWice/recovery.html
Hope this still helps.
So, to get this tablet in Recovery Mode, hold the volume button then hold the On button.
If the tablet is in a boot loop, then press the Reset button to turn it off, or to flash it.
With this recovery image, to recover the /data partition go under 'apply update from cache', then select the entry with 'Yes- <something>'
I know that is weird, but it took me a bit to find that out.