Comment 2 for bug 1536810

For full disclosure, this is in a "cross" build environment (qemu-static).
this works for other versions of ubuntu and has worked for xenial in the past.

the error messages seem to indicate 'update-initramfs' was deferred, but the the postinst tried to copy it into place even though it wasnt there. I am able to hack around this error by just touching the file /boot/initrd.img-4.3.0-7-generic before runnign the apt-get install.

Setting up linux-image-4.3.0-7-generic (4.3.0-7.18) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
/bin/cp: cannot stat '/boot/initrd.img-4.3.0-7-generic': No such file or directory
Failed to copy /boot/initrd.img-4.3.0-7-generic to /boot/initrd.img at /var/lib/dpkg/info/linux-image-4.3.0-7-generic.postinst line 745.