That's the original H8 with Allwinner A31 chipset, from ~ 2014.
The one we sold (which had a Rockchip 3368 chipset) was the next generation. H8 Lite came later and has similar hardware to the Rockchip 3368 H8.
Because we didn't sell it I have very little info, sorry. Searches on Google don't yield much either so it's going to be difficult getting firmware. You could try emailing HiMedia: export@himedia.cn