KernelBootParameters

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[[https://help.ubuntu.com/community/BootOptions/#Change Boot Options Temporarily For An Existing Installation|Instructions for earlier releases]] are also available. These instructions are applicable to [[https://help.ubuntu.com/community/Grub2|GRUB 2]], the boot loader in Ubuntu 9.10 and later releases.
Earlier Ubuntu releases used [[https://help.ubuntu.com/community/GrubHowto|GRUB]];
Instructions for
[[https://help.ubuntu.com/community/BootOptions/#Change Boot Options Temporarily For An Existing Installation|changing boot parameters in earlier releases]] are also available.

How to Add a Kernel Boot Parameter

  • * * * WORK IN PROGRESS * * *

Kernel boot parameters are text strings which are interpreted by the system to change specific behaviors and enable or disable certain features. Kernel boot parameters ...

  • are case-sensitive
  • are sometimes just simple words ("splash" or "noapic")

  • sometimes have = signs with various possible values ("acpi_backlight=vendor")

  • sometimes include punctuation ("i8042.noloop")

Always enter kernel boot parameters exactly as advised. Errors in spelling or formatting or invalid values will not result in any error message -- they will simply have no effect.

These instructions are applicable to Ubuntu 9.10 and later releases

These instructions are applicable to GRUB 2, the boot loader in Ubuntu 9.10 and later releases. Earlier Ubuntu releases used GRUB; Instructions for changing boot parameters in earlier releases are also available. Systems which were upgraded from Ubuntu 8.04 to 9.10 may also need to use the instructions for earlier releases.

Temporarily Add a Kernel Boot Parameter for Testing

  1. Restart your system, or shut it down and then power it on again.
  2. Press and hold down the SHIFT key immediately and keep it held down while the system starts to boot, in order to force the "GNU GRUB" menu to appear. (If the system boots up without displaying the "GNU GRUB" menu, try pressing the ESC key instead of holding down SHIFT and see the "earlier releases" instructions above).

  3. Once the "GNU GRUB" menu appears, release SHIFT and then press the e key to enter edit mode.

  4. Use the down arrow key to move the cursor to the line beginning with the word "linux", then press the END key to move the cursor to the end of that line. Normally this will be just after the words "quiet splash".

  5. Press SPACE to add a blank space (after "splash") then carefully type in the kernel boot parameter that you need to add. (If you need to add multiple parameters separate them with SPACE but do not add spaces before or after any = signs or punctuation in the parameters themselves).

  6. Press Ctrl+X to boot the system using the parameters you've added.

Note: The parameter(s) you've added to the linux line are only temporary: They will affect this boot session, but once you restart the system they will no longer be in effect.

Permanently Add a Kernel Boot Parameter

  1. Log in to the system and start a terminal window (Applications->Accessories->Terminal).

  2. In the terminal window, enter the command:sudo gedit /etc/default/grub

    • Enter your password when prompted by [sudo].
    • (If the file /etc/default/grub appears to be empty or does not exist, see the instructions for earlier releases above).

  3. In the editor window, use the arrow keys to move the cursor to the line beginning with "GRUB_CMDLINE_LINUX_DEFAULT" then edit that line, adding your parameter(s) to the text inside the double-quotes (normally after the words "quiet splash"). Click the Save button then close the editor window.

  4. In the terminal window, enter the command:sudo update-grub

  5. Restart the system.

Note: The parameter(s) you've added to the GRUB_CMDLINE_LINUX_DEFAULT line are persistent, and will be in effect for every subsequent boot session (unless you remove them by repeating the procedure above).

Kernel/KernelBootParameters (last edited 2022-12-02 14:25:41 by merlijn-sebrechts)