Can't clean a full /boot because of unmet dependencies
In such case I would use the dpkg
tool to force the removal of some kernel packages.
This is not suggested for common use and is a bit dangerous, but in such case with unmet dependencies might help.
First of all locate the kernel in which the system is booted. The one that is currently loaded. Open a terminal (CTRL+ALT+T) and issue the following command
uname -r
It will show you the loaded kernel, you should NOT try to remove this one.
Then issue the command
ls /boot
it will return all the installed images. Pick one or two and try to remove them. Try to force remove/purge them. For example
sudo dpkg --force-all -P linux-image-3.13.0-32-generic
You can do the same for other images, in order to free up some space.
Then you can try to install the missing packages, or
sudo apt-get install -f
to try resolve the dependencies.
Finally, issue the "cleanup old kernels" command
sudo apt-get purge $(dpkg -l linux-{image,headers}-"[0-9]*" | awk '/ii/{print $2}' | grep -ve "$(uname -r | sed -r 's/-[a-z]+//')")
Above command will remove ALL the kernels except the one that is currently loaded.
Because you have a separate /boot partition, keep in mind you will need to track its space and cleaning up often (the frequency depends on the space of /boot)
This is what worked for me on Ubuntu 16.04.
sudo apt autoremove --purge
sudo apt autoremove
sudo apt-get -f install
sudo apt-get upgrade
List all kernels:
dpkg --list 'linux-image*'
Display current kernel:
uname -r
List all kernels EXCEPT current one:
dpkg -l linux-{image,headers}-"[0-9]*" | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e '[0-9]'
Make sure your current kernel isn't on that list.
Remove all kernels EXCEPT current one:
dpkg -l linux-{image,headers}-"[0-9]*" | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e '[0-9]' | xargs sudo apt-get -y purge
Clear other stuff:
sudo apt-get autoremove
If it stills throws any error then repeat following commands to remove unwanted kernels,
sudo dpkg --purge linux-image-X.X.X-XXX-generic linux-image-extra-X.X.X-XXX-generic linux-signed-image-X.X.X-XXX-generic
sudo dpkg --purge linux-image-Y.Y.Y-YYY-generic linux-image-extra-Y.Y.Y-YYY-generic linux-signed-image-Y.Y.Y-YYY-generic
sudo apt-get -f install
dpkg -l linux-{image,headers}-"[0-9]*" | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e '[0-9]' | xargs sudo apt-get -y purge