tell me - in more technically detailed terms, how would upgrading the kernel cause serious compatibility issues with firmware? Heck, Luke-Jr was able to get a 2.6.32+ kernel booting on the Nokia N800/N810, even the N770 was able to run newer kernels! - I don't see why it's not the same for the N900. Sure the N900 has diffrent hardware - but i don't see how it's not possible. Come on, guys!, where is your maemo spirit! I know this community can do it!
I think this thread should be merged with the one Flandry pointed to.