OK... The weirdest thing happened. I started downloading the "smaller" Switzerland file and.... it kept downloading over 180MB until over 1GB.... Yes it was just a false report on file size.

Anyway i did the flash on windows and it kept giving me errors. It was something about update requests and they were random (every time at different % point) so I thought it was checking something online. Switching off the internet did the trick and flashed the image successfully.

However it did not delete personal data. After that much trouble I noticed there is "clear device" option on reset menu.... Why anyone told me??? Anyway it REALLY clears everything. Even stock nokia things like wallpapers so I enjoyed it. Clean N9 from the beginning!