about being free with N9:
http://www.developer.nokia.com/Commu...g/n9-developer

"The current public device image for N950 was released on 2011-08-30. The image is contains the week 34 release of the platform. The one click flasher-tool to update the device is available for Windows, Linux and Mac OS X environments. A device image and tooling for N9 will be made available as well, and both of them will evolve as the corresponding updates are published for the devices."

So I guess that even if flashing another kernel, we can go back to official image (for instance for warranty).