Update to 4.4.0-109
```
sudo apt-get update
sudo apt-get install linux-headers-4.4.0-109 linux-headers-4.4.0-109-generic \
linux-headers-generic linux-image-4.4.0-109-generic \
linux-image-extra-4.4.0-109-generic linux-image-generic \
linux-tools-4.4.0-109 linux-tools-4.4.0-109-generic linux-tools-generic
uname -a
// output: Linux ubuntu-xenial 4.4.0-109-generic...
```
Reboot to the last working kernel and remove 4.4.0-108-generic:
1. press Shift between UEFI/BIOS and login-screen to enter GRUB
2. in GRUB select Advanced options for Ubuntu and select Ubuntu, with Linux 4.4.0-xxx-generic (where xxx <108)
3. Login to the system and remove this buggy 4.4.0-108-generic and install 4.4.0-104-generic instead.
```
sudo apt-get purge linux-headers-4.4.0-108 linux-headers-4.4.0-108-generic \
linux-image-4.4.0-108-generic linux-image-extra-4.4.0-108-generic \
linux-tools-4.4.0-108 linux-tools-4.4.0-108-generic
sudo apt-get autoremove
sudo apt-get install linux-headers-4.4.0-104 linux-headers-4.4.0-104-generic \
linux-image-4.4.0-104-generic linux-image-extra-4.4.0-104-generic \
linux-tools-4.4.0-104 linux-tools-4.4.0-104-generic
```
> Ref:
> * [Kernel panic after update to 4.4.0-108-generic](https://askubuntu.com/a/994277)
> * [Meltdown update kernal doesn't boot](https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1742323?ref=stackshare)