Comment 4 for bug 1827157

The package "linux-image-4.18.0-15-generic" contains the missing file "/boot/vmlinuz-4.18.0-15-generic".

However, if you try to install this package, apt gives a message that the package is already installed:

$ apt install linux-image-4.18.0-15-generic
    Reading package lists... Done
    Building dependency tree
    Reading state information... Done
    linux-image-4.18.0-15-generic is already the newest version (4.18.0-15.16~18.04.1).
    linux-image-4.18.0-15-generic set to manually installed.

However, passing the "--reinstall" flag to apt solves this problem:

$ apt install --reinstall linux-image-4.18.0-15-generic

You can see that all required file are installed:

$ ls -1 /boot/{vmlinuz,initrd}*
    /boot/initrd.img-4.18.0-15-generic
    /boot/initrd.img-4.18.0-18-generic
    /boot/vmlinuz-4.18.0-15-generic
    /boot/vmlinuz-4.18.0-18-generic

Cubic's ISO Boot Kernel tab now correctly the vmlinuz and initrd file versions.