freeup-boot-partition.sh

# First check your kernel version, so you won't delete the in-use kernel image, running:
 
uname -r
# Now run this command for a list of installed kernels:

sudo dpkg --list 'linux-image*'
# and delete the kernels you don't want/need anymore by running this:

sudo apt-get remove linux-image-VERSION
# Replace VERSION with the version of the kernel you want to remove.

# When you're done removing the older kernels, you can run this to remove ever packages you won't need anymore:

sudo apt-get autoremove
# And finally you can run this to update grub kernel list:

sudo update-grub