MK809IV 2GB 8GB crashes at booting

Hi all,
This is my first post here and I am new in trying to fix MK809IV with probably Rock Chip 3229 (read bellow)
My problem is that the device worked fine for about one month without any problem. The device plastic case looks to me warm, I presume that the chip must be hot. Usually when I turned OFF the TV I turned the device OFF from the socket plug too (I could not power it from the TV, it does not worked when it was powered from the TV). Ones I forgot to turn it OFF left it powered ON for 2days (or three). One day I wanted to watch the TV via android box and this happened (please see the video from 0:40)

https://www.youtube.com/watch?v=Vni7ZHr8bmU&t=7s

Is there any way to fix it? All three socket power supply are 2.0A. The device was working fine before on any of them.

I opened the device to see what chip is inside. Please see the photo:





There is some "heat sink" but not too efficient. On the other side the thermal paper was damaged by the heat.

Due to the heat sink I could not read the chip number, but it is the same device as on this video

https://www.youtube.com/watch?v=Nrx-fFcdBW4

so the chip must be Rock Chip 3229. The guy is showing the 8GB NAND Flash, but on my device it is missing. Why it is not there. In the description where I bought it was written MK809IV 2GB RAM, 8GB

So I have two question:
1. What type of issue is that, what I have with the device (https://www.youtube.com/watch?v=Vni7ZHr8bmU&t=7s) and how to fix it
2. Why there is no NAND Flash, where is than android OS located (I thought it is on the NAND Flash). Did just Chinese wanted to save some money and did not soldered it in to board? Or because the heat sink? But than the device is not 8GB? I did not checked it when the device was running...what a shame....

Thanks you for help and reply.