Seicane unit screen problem

Hi,

I have a problem with the screen: the image is smaller than the screen.
The unit is: Seicane/ MTCB-KLD2-V2.81/ARM Cortex-A9 @1.6GHz (x4)/ rk3188-eng4.4.4 27112015/Kernel root@chun#1704
The problem can be seen in the photos attached.
The story is:
-Initially I had a problem with the system sounds (touching any button triggered a sound). I tried to reduce the volume from factory settings. the unit didn't kept the settings. They sent me the first update img file. It didn't solve the problem.
-They sent a 2ndimg file that solved the sound problem but the image shortened.
-The 3rd update img file still didn't solved the screen problem.
At the 2nd update I chose to wipe data and format flash. Probably that was what caused the image problem.
Now if I check the resolution, this is 480x800. On their website (seicane SKU: 118328 Model:S168073) it says HD 1024x600.
I rooted the 2nd update version with Kingroot and used an app to change the resolution: it changed it but with the same dimension of the image (only icons size changed)
I would need something to stretch the image over the whole screen.

Any ideeas?

Thanks.
i65.tinypic.com/4v3kgo.jpg
i66.tinypic.com/6qe9g6.jpg