$ cat /etc/zipl.conf 
[defaultboot]
default=ubuntu
target=/boot/
[ubuntu]
  image=/boot/vmlinuz
  ramdisk=/boot/initrd.img
  parameters="root=/dev/mapper/vg_ubuntu-root"

$ ls -latr /boot/bootmap 
-rw------- 1 root root 69632 Jan  6 10:13 /boot/bootmap