Thanks. I'm building a test kernel in OBS home:tiwai:leap-15.0-helix repo. It'll appear later at http://download.opensuse.org/repositories/home:/tiwai:/leap-15.0-helix/standard/ Please check it later whether it works without the boot option. Note that the kernel package release number may be lower than others, so you'd better to increase the number of kernels to keep on your system by editing /etc/zypp/zypp.conf (about kernel multiversion).