Drivers I would assume is another issue since with a new kernel the old development drivers are non functional... So its like running a new ver of android on an old device. With some work you can get it too boot, but then things like camera, WiFi, etc won't work.
But it is nice even with all the issues to see that in fact WP8 can run on old hardware. If if all it does is pose for the cameras.
Sent from my HTC One XL using xda app-developers app