IT/Software/System Config/grub

Grand Unified Boot Loader

this is the default in linux.

Runs really well but has never been really intuitive to make changes

BECAUSE you normally should not be messing around in here.

Make the menu appear

• If only linux is instsalled the menu will not appear by default
  • There are several menus/Interfaces during bootup.
  • BIOS
    • This is very low level where the computer looks for hard drives
    • It checks to make sure everything is in place to boot.
  • Grub
    • This is the screen where you can pick what Operating System to Boot
    • You can perform some recovery operations
    • Hitting any of the arrow keys will stop the timer so you can look at it.
  • Login
    • Here is where you login to the operating system that your or Grub chose
• There are many cases where the menu will not appear.
  • I don't know exactly why the defaults are chosen and why they seem to be random.
• UEFI
  • You have to hit the escape key after bios and before grub.
    • VERY TRICKY
• Non-UEFI (legacy)
  • Hold down the shift key from power on.

Change the boot order

Boot the last booted

• Open the file for editing

sudo nano /etc/default/grub

• Now add the following two lines
  

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true

Boot anything in the list

sudo update-grub

• Take note of the items.
• It is zero based indexing so the first entry is zero and so on.
• Now open the grub file and change the DEFAULT to the one you want.
• Update Grub again

sudo update-grub