To revert to the latest recommended kernel:

<pre class="wp-block-code">```
sudo apt-get install --install-recommends linux-generic-hwe-18.04

To maintain the kernel and cleanse the unused:

```
You should check partially removed kernels with

dpkg -l linux-image-\* | grep ^rc

and remove them with for example sudo apt-get purge linux-image-4.4.0-101-generic.

Purging will remove initramfs generation rules from /var/lib/initramfs-tools/.

If it does not help, you can remove them manually from initramfs list:

sudo rm /var/lib/initramfs-tools/3.13.0-39-generic
sudo rm /var/lib/initramfs-tools/4.4.0-101-generic
sudo rm /var/lib/initramfs-tools/4.4.0-103-generic
sudo rm /var/lib/initramfs-tools/4.4.0-38-generic
sudo rm /var/lib/initramfs-tools/4.4.0-45-generic
sudo rm /var/lib/initramfs-tools/4.4.0-59-generic
sudo rm /var/lib/initramfs-tools/4.4.0-77-generic
sudo rm /var/lib/initramfs-tools/4.4.0-78-generic
sudo rm /var/lib/initramfs-tools/4.4.0-81-generic

Usually I run purge-old-kernels followed by sudo apt-get autoremove to have only 2 recent kernels.

You can reinstall installed kernels with their initramfses:

sudo apt-get install --reinstall \
$(dpkg -l linux-image-\* | grep ^ii | awk '{print $2}')

```
```

ref: <https://askubuntu.com/questions/1001285/why-are-old-initrd-files-of-uninstalled-kernels-filling-up-boot-partition>