What is the capacity of your SD (in GB)?

...But then the root folder "/" has nofiles like autorun or something like that...
I don't know if I understand what you says.
If this disk / folder with the symbol "/" is in the SD, it will be some configuration created by the WinCE operating system.
This is related to the device’s RAM and in practice is found at the root of the device.
Take a picture of what's going on.
...other folders from a dashcam: photos,videos and events from which I think it should not matter...
It doesn't matter for anything, it doesn't interfere in the process.