Since http://cdimage.ubuntu.com/netboot/12.04/ is now offering the possibility to load images with distinct kernels (which wasn't like that in November 2013) I assume that the problem is solved by using the netinstall image with kernel 3.11.
Since http:// cdimage. ubuntu. com/netboot/ 12.04/ is now offering the possibility to load images with distinct kernels (which wasn't like that in November 2013) I assume that the problem is solved by using the netinstall image with kernel 3.11.