Ok I tried some things out.
1. I booted from the original Linux SD (which came with the Nano DE-10) and tested the USB hub. Mouse and Keyboard did not work. If the Mister update broke anything at least this should have worked in my opinion.
2. I connected the Nano DE-10's USB OTG port directly to my PC. According to the Nano DE-10 manual this should make the SD-card from Mister visible as a mass storage device. But nothing happened.
I have no means to test my USB hub since I have no other devices which connect to Micro USB A/B. But I think from the above tests the conclusion can me drawn that the port on the Mister is damaged.
What can you make of this?
John