My first intention when I was thinking about this project was to be able to control the hoverboard without any major modifications of the hoverboard so anyone can rebuild this. However, I tried to analyze the packets exchanged between the two boards, but whenever I connect the Arduino to the hoverboard, it shuts down after a few seconds. I couldn't figure out why this is happening, maybe it caused by the firmware or something else. 

Afterword, I did some researches, and I found that there are project that used the same hoverboard I have (hoverboard with two main boards). So I decided that I'll follow their lead even if this will require uploading a new firmware to the hoverboard, and maybe later I'll come back to continue on my first idea.

Fortunately, due to the "magic of open source",   there are many projects and github repos hat give instruction on how to do this (The first project I found is Hoverboards for Assistive Devices,  that uses the  Hoverboard-Firmware-Hack-Gen2).  At this moment I don't have an ST-Link programmer in order to program the onboard ship (GD32F-130), I ordered one and I will continue the project when I receive it.