Hi Alex,
Thanks for the quick response. You are right, I was referring to the LINUX_IMAGE_FOR_SD... that's what is on the sdcard and is booting ok. I checked it by entering with putty via serial and executing some linux commands as root.
Regarding the board firmware update, I missed section (6) of the getting started doc and was trying to do it manually as explained on section (12). My bad 
So I successfully upgraded the firmware using the IDE and automatically the Centrino WiFi started to work with the bundled IDE examples.
This is awesome!
- Many thanks Alex!