Comment 5 for bug 1508157

We can also see that the 4.2 kernel is actually installed during the upgrade:

4612 Setting up linux-image-4.2.0-16-generic (4.2.0-16.19) ...^M
4613 Running depmod.^M
4614 update-initramfs: deferring update (hook will be called later)^M
4615 Examining /etc/kernel/postinst.d.^M
4616 run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.2.0-16-generic /boot/vmlinuz-4.2.0-16-generic^M
4617 run-parts: executing /etc/kernel/postinst.d/dkms 4.2.0-16-generic /boot/vmlinuz-4.2.0-16-generic^M
4618 run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.2.0-16-generic /boot/vmlinuz-4.2.0-16-generic^M
4619 update-initramfs: Generating /boot/initrd.img-4.2.0-16-generic^M
4620 run-parts: executing /etc/kernel/postinst.d/pm-utils 4.2.0-16-generic /boot/vmlinuz-4.2.0-16-generic^M
4621 run-parts: executing /etc/kernel/postinst.d/unattended-upgrades 4.2.0-16-generic /boot/vmlinuz-4.2.0-16-generic^M
4622 run-parts: executing /etc/kernel/postinst.d/update-notifier 4.2.0-16-generic /boot/vmlinuz-4.2.0-16-generic^M
4623 run-parts: executing /etc/kernel/postinst.d/zz-update-grub 4.2.0-16-generic /boot/vmlinuz-4.2.0-16-generic^M
4624 Generating grub configuration file ...^M
4625 Found linux image: /boot/vmlinuz-4.2.0-16-generic^M
4626 Found initrd image: /boot/initrd.img-4.2.0-16-generic^M
4627 Found linux image: /boot/vmlinuz-3.19.0-30-generic^M
4628 Found initrd image: /boot/initrd.img-3.19.0-30-generic^M
4629 Found linux image: /boot/vmlinuz-3.19.0-14-generic^M
4630 Found initrd image: /boot/initrd.img-3.19.0-14-generic^M
4631 Found memtest86+ image: /boot/memtest86+.elf^M
4632 Found memtest86+ image: /boot/memtest86+.bin^M

I've been unable to recreate the removal of the kernel on a virtual machine with only 1 operating system with or without the nvidia-304 package installed.