Nokia is the originator of the claim that overclocking will void your warranty. I think that Nokia's intent in making that statement was to serve notice that Nokia would not fix damage caused by overclocking. Since no one has yet demonstrated overclocking damage on the N900, it is a moot point. In fact, the hysterical anti-overclocking claims by many of the best and brightest on this site have mostly been disproved by the passage of time. But of course, this is quite an old story by now.