install requirements:
sudo apt-get install -y linux-image-extra-virtual
run:
echo "snd-aloop" >> /etc/modules
modprobe snd-aloop
/etc/default/grub
file:
GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true
GRUB_DISABLE_SUBMENU=y
export GRUB_CONFIG=`sudo find /boot -name "grub.cfg"`
sudo update-grub
run:
sudo grep 'menuentry ' $GRUB_CONFIG | cut -f 2 -d "'" | nl -v 0
will list something like this
0 Ubuntu, with Linux 4.18.0-15-generic
1 Ubuntu, with Linux 4.18.0-15-generic (recovery mode)
2 Ubuntu, with Linux 4.15.0-99-generic
3 Ubuntu, with Linux 4.15.0-99-generic (recovery mode)
4 Memory test (memtest86+)
5 Memory test (memtest86+, serial console 115200)
we want to make Ubuntu, with Linux 4.15.0-99-generic
kernel, the default one:
sudo grub-set-default 2
also we can boot on a specific kernel temporarely using: `sudo grub-reboot