Luckily, my KIA dealership is not far from where I live, so there isn't too much bother to bring it in. Otherwise, it would be frustrating.
It seems the technicians doesn't have much experience with KIA Soul EV. They had never heard about the problem of blinking SOC bars, and they had no experience in changing the instrument cluster. But I take it they will be better prepared the next time they will try.
They received the USB-stick with the upgrade for the car the very same day I was there, and they did not have any clues of what the changes or fixes the upgrade contained. I will ask if they have more information about the software upgrade the next time I am there. I don't even know if the dealership knows what part of the car the upgrade effects. But as I said, it is vacation time here in Norway, so that might be why there seems to be difficult for them to know.