Hi Koepel,
Thanks for the answer!
I don't have a comupter with Windows 10.
Can you explain why it is not an official Arduino board? I mean, KOSMOS advertise it as an Arduino Uno being comprised in the box. The box being 80EUR, I neither did consider it to be "worst possible quality". On the other hand, I didn't buy it for the Arduino, specifically, and hence had no idea, what a "proper-priced" Arduino should cost. However, on this site (arduino.cc), the one called "Rev 3" looks quite similar to the one I have, and costs 20EUR.
Or did you mean the Bootloader?
I did not install the zadig-drivers. I suppose, after checking their website, that these are drivers? Does the Bootloader need these particular drivers?
Thanks again!