Comment # 12 on bug 947704 from Stefan Seyfried

changing my pxelinux.cfg stanza to

LABEL InstallLEAP
  MENU LABEL Install LEAP Beta
  KERNEL /memdisk
  APPEND initrd=/LEAP/leap.iso harddisk=1

INCLUDE pxelinux.cfg/default.iso

makes memdisk 0x81 and the built-in disk 0x80. With this, I get a installation
proposal without yast crashing. I have not yet proceeded with the installation
(because the system is already zypper dup'ed to Leap), but this really looks
like the root of the problem: only BIOS drive 0x81 available but no 0x80.