last result... may be it can be related to Nvidia driver. What I did: I wanted to try 3.x kernel (like my working 13.2 install), so found one on the obs. This one installed not only 3.x kernel, but also some "pv" and "xen" 4.1 kernels. The only relevant thing is that those kernels didn't boot either, but displayed nvidia related error messages, that lead me to use the "nomodeset" option. Since them Leap seems to boot. I could reinstall the default 4.1 kernel from openSUSE and boot. Of course I may have been lucky, as it was already some times ago, but I still wanted to share my result. If the problem is really solved, I of course will report here thanks jdd