This video covers how to update the firmware of your Bittboy and pocketgo! This same method works for the LDK, rs-97 and the rg300.
Good news is that the latest firmware improves the screen tearing issues by at least 80%. In the end of the video I did a fast comparison between the LDK, pocketgo (post fix) and the bittboy (pre fix), in slow-motion and the results are very pleasing!

Pocketgo :

Pocketgo V1.3:!YkhTjIpQ!DwrhnZImN7hpqXk1FKMXbYYyVwWN8AiOzAeFLex7f2Q

Bittboy V2 V2.5:!IkoRHKKY!hCsSmSvLFArO59gU_5LeSz655xu-TJYBe0CDhvQu1_g

Bittboy V3:!R04zGIZT!35PY35LDh-RvuIM-iJ16SeVEbs2AdnMoRk3-wXDIItQ

Bittboy V3.5:!h0RVTABQ!SFPkogkERNX0w7yiYmkjfuOyPwLk2QheW-fvdA_fzpE

Tools you need to download:

Minitool partition wizard: