f1upgradeutility.exe using 100% CPU

In the hope of making the Google results for f1upgradeutility.exe a little more helpful, I'd like to note that this application using 100% (or 50% or 25% depending on the number of cores you have) of CPU is usually found in c:\Program Files\NSS\f1upgradeutility.exe and belongs to the Nemesis Service Suite, which you've probably installed to flash your Nokia device.