The problem here is the installer failed to build/install initrd.img.
After installing into a LVM LV via libvirt and seeing the error I mounted the disk image contained in the LV and explored:
$ sudo losetup -f --show -P /dev/VG02/lubuntu1910 /dev/loop5 $ sudo mount /dev/loop5p1 /mnt/target $ sudo TERM=screen chroot /mnt/target
# ls -l /boot/ total 13548 -rw-r--r-- 1 root root 224306 Jun 4 16:22 config-5.0.0-17-generic drwxr-xr-x 5 root root 4096 Jun 18 20:50 grub lrwxrwxrwx 1 root root 27 Jun 18 17:41 initrd.img -> initrd.img-5.0.0-17-generic lrwxrwxrwx 1 root root 27 Jun 18 17:41 initrd.img.old -> initrd.img-5.0.0-17-generic -rw-r--r-- 1 root root 182704 Jan 28 2016 memtest86+.bin -rw-r--r-- 1 root root 184380 Jan 28 2016 memtest86+.elf -rw-r--r-- 1 root root 184840 Jan 28 2016 memtest86+_multiboot.bin -rw------- 1 root root 4378278 Jun 4 16:22 System.map-5.0.0-17-generic lrwxrwxrwx 1 root root 24 Jun 18 17:41 vmlinuz -> vmlinuz-5.0.0-17-generic -r--r--r-- 1 root root 8703736 Jun 18 20:50 vmlinuz-5.0.0-17-generic lrwxrwxrwx 1 root root 24 Jun 18 17:41 vmlinuz.old -> vmlinuz-5.0.0-17-generic
Notice the symlinks from initrd.img{,.old} point to non-existent initrd.img-5.0.0-17-generic,
The problem here is the installer failed to build/install initrd.img.
After installing into a LVM LV via libvirt and seeing the error I mounted the disk image contained in the LV and explored:
$ sudo losetup -f --show -P /dev/VG02/ lubuntu1910
/dev/loop5
$ sudo mount /dev/loop5p1 /mnt/target
$ sudo TERM=screen chroot /mnt/target
# ls -l /boot/ 5.0.0-17- generic img-5.0. 0-17-generic img-5.0. 0-17-generic _multiboot. bin map-5.0. 0-17-generic 5.0.0-17- generic 5.0.0-17- generic 5.0.0-17- generic
total 13548
-rw-r--r-- 1 root root 224306 Jun 4 16:22 config-
drwxr-xr-x 5 root root 4096 Jun 18 20:50 grub
lrwxrwxrwx 1 root root 27 Jun 18 17:41 initrd.img -> initrd.
lrwxrwxrwx 1 root root 27 Jun 18 17:41 initrd.img.old -> initrd.
-rw-r--r-- 1 root root 182704 Jan 28 2016 memtest86+.bin
-rw-r--r-- 1 root root 184380 Jan 28 2016 memtest86+.elf
-rw-r--r-- 1 root root 184840 Jan 28 2016 memtest86+
-rw------- 1 root root 4378278 Jun 4 16:22 System.
lrwxrwxrwx 1 root root 24 Jun 18 17:41 vmlinuz -> vmlinuz-
-r--r--r-- 1 root root 8703736 Jun 18 20:50 vmlinuz-
lrwxrwxrwx 1 root root 24 Jun 18 17:41 vmlinuz.old -> vmlinuz-
Notice the symlinks from initrd.img{,.old} point to non-existent initrd. img-5.0. 0-17-generic,