Format the internal SD card to FAT, install into tablet, then format another SD card to FAT then copy the firmware2 and firmware-discovery files to the card, insert in the side slot on the tablet, boot the tablet and it shoud start the update. After the update tells you it's complete take out the sd card or it will start the update again . The problem might have something to do with not installing from second SD card. (you could try to update without re formatting the internal card to see if it works)
Hope that helps you out.