As I said in my post, we're actively upstreaming the kernel drivers (as they're open source) so they're also maintained in the main kernel ecosystem. In addition to that, we have to maintain N900 in MeeGo as a reference device and we do update to newer kernels.. I mean, we did a .28 -> .33 -> .34 -> .35 already. It gets easier each time as more and more code is in upstream..