turn on grub menu
if your grub menu don’t show when you boot up your system , you can follow this :
edit grub config
1sudo vim /etc/default/grub
1# GRUB_TIMEOUT_STYLE=hidden
2GRUB_TIMEOUT=10
commit
1sudo update-grub
get a theme
change some grub settings
edit grub config
1sudo vim /etc/default/grub
find and change:
1GRUB_DEFAULT=saved
add this line
1GRUB_SAVEDEFAULT=true
this 2 line make grub rember your choice
commit
1sudo update-grub