I think that I've found a bug with the new Option ROM. It won't let me use the Official Intel WHQL RST driver Version 10.6.0.1002.
Don't ask me what's wrong but trying to install the drivers fails with an error telling me that some stuff couldn't be installed.

Anyway I could fix it with using the Intel WHQL RST driver Version 10.5.1.1001. This one can be downloaded from Station-Drivers.