How do I add a kernel boot parameter?

1

To temporarily add a boot parameter to a kernel:

Start your system and wait for the GRUB menu to show (if you don't see a GRUB menu, press and hold the left Shift key right after starting the system). Now highlight the kernel you want to use, and press the e key. You should be able to see and edit the commands associated with the highlighted kernel. Go down to the line starting with linux and add your parameter foo=bar to its end. Now press Ctrl + x to boot.


To make this change permanent:

From a terminal (or after pressing Alt + F2) run:

gksudo gedit /etc/default/grub

(or use sudo nano if gksudo or gedit are not available) and enter your password.

Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT and append foo=bar to its end. For example:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash foo=bar"

Save the file and close the editor.

Finally, start a terminal and run:

sudo update-grub

to update GRUB's configuration file (you...

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I need to add the boot parameter foo=bar to my kernel. How can I do this once for testing, and permanently if testing was a success?

To temporarily add a boot parameter to a kernel:

Start your system and wait for the GRUB menu to show (if you don't see a GRUB menu, press and hold the left Shift key right after starting the system). Now highlight the kernel you want to use, and press the e key. You should be able to see and edit the commands associated with the highlighted kernel. Go down to the line starting with linux and add your parameter foo=bar to its end. Now press Ctrl + x to boot.


To make this change permanent:

From a terminal (or after pressing Alt + F2) run:

gksudo gedit /etc/default/grub

and enter your password.

Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT and append foo=bar to its end. For example:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash foo=bar"

Save the file and close the editor.

Finally, start a...

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On 05/07/2012 11:27 AM, Jeremy Jongepier wrote:


> On 05/07/12 04:14, Diego Simak wrote:
>> Hi, sorry but I don't really know how to do this, I don't know even if it
>> is possible, I mean, just enable threadirq option using kernel parameters
>> only.
>>
>> Maybe some other people can put a light on this for both of us;-)
>>
>> have fun
>> Diego
>
> You could try adding a built-in kernel command string (Processor type
> and features - Built-in kernel command line). Never tried this so not
> sure if it works.

Had a look at that using menuconfig, and it was simple enough. First

enable the "Built-in kernel command line", after which you need to use

the "+" key to add a field for your argument(s).

The result in the config file was..

CONFIG_CMDLINE_BOOL=y
CONFIG_CMDLINE="threadirqs"
# CONFIG_CMDLINE_OVERRIDE is not set

>
> Best,
>
...

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The Linux kernel can be supplied with various parameters during boot time or at run time. These parameters customize the default behavior of the kernel, or inform the kernel about hardware configuration. Kernel parameters can be changed at run time by modifying files in /proc or /sys, while certain kernel parameters need be passed to the kernel at boot time by a boot loader such as GRUB or LILO.

In this tutorial, I will describe how to add kernel boot parameters via GRUB on Linux.

If you want to change or add kernel parameters when you are using GRUB boot loader, you can edit GRUB config file. The following are distro-specific ways to add kernel boot parameters to a GRUB config file.

Add Kernel Boot Parameters on Debian or Ubuntu

If you want to add kernel parameters during boot time on a Debian based system, edit GRUB config template at /etc/default/grub. Add a kernel parameter in the form of "name=value" in GRUB_CMDLINE_LINUX_DEFAULT variable.

...

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I was able to get my hp zt3300 past the PAE failure by editing the boot files on partition sdc12 (the actual boot partition). This got me past the PAE
problem and I got the "Cloudready" screen but it stated that the "system
is repairing itself" and then rebooted. It stayed stuck in this loop of booting
and "system is fixing itself" until I stopped it.

I also tried getting the latest Chromium build from chromium.arnoldthebat.co.uk in the "special" directory.
The Cx86* builds are non-pae and do not need editing of boot files to work
on a non-pae computer. Unfortunately I got the same failure as above
with "repairing" and rebooting.

Unfortunately there is not enough information in "repairing" to tell what
is going wrong.

It will take familiarizing with the ChromiumOS Kernel Faq and Developer Guide to tell what it causing the problem.

You could try the older builds at chromium.arnoldthebat.co.uk in the special directory...

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This document provides simple instructions for adding a kernel boot parameter to an Ubuntu system using GRUB 2.

When advised to try using a particular kernel boot parameter, it is usually a good idea to first add the parameter temporarily for testing. Once you have determined that adding the parameter has the desired effect, you can then add it permanently. Directions for both methods are below.

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 a simple word ("splash" or "noapic")

sometimes have an = sign 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....

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When GRUB 2 came out it was different in that grub.conf was no longer supposed to be edited by the user; the distro package manager would do whatever and then there was supposed to be a means for the user to make changes using some kind of tool that was not documented at that time (I'm sure they have lots of nice docs for it now, of course ;|).

I believe part of the goal was to simplify things by adding a layer of abstraction. I'm not so sure how well that worked out, and (full disclosure) I've never bothered to do things the grub 2 "right way". The the "wrong" way is just too easy, and it will work for you here:

Despite the warning at the top of the file, you can edit it. The distro installer will modify it when the kernel is updated and will leave your entries alone (at least, on Fedora, Ubuntu, and I am pretty sure Debian), although it may add one to the top and make it default, so when that happens, you'll have to move some entries around or change the index in...

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Possible Duplicate:
How do I add a kernel boot parameter?

I'm looking for a way to fix this bug the way described here.

But I don't know how to edit boot options in Kubuntu. In my distribution there's no /boot/grub/menu.lst file and also the grub.cfg in same folder does not have a line starting with kernel.

I'm really clueless about adding these options!

The /boot/grub/menu.lst was a very old way of configuring GRUB and it's boot options. I think I used to use it like that in Ubuntu 10.10 and below. Right now, if you are using a updated version of Kubuntu, the option should be in /etc/default/grub

Just do something like:

sudo nano /etc/default/grub (To edit via terminal)
sudo gedit /etc/default/grub (To edit via GUI)

The option you want to edit is:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX=""

You can either add what you want after the splash parameterin the first line or add inside the quoted part...

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Changing or editing your kernel boot parameters is very important when you want to fix an issue that causes errors during boot, or test a new feature, activate a different driver, or disable a feature on your system. These parameters are stored as text, in the boot loader’s configuration file which the kernel parses during the “init” process. To determine what parameters were used during your system’s last boot, you should enter the following on a terminal:

cat /proc/cmdline

The usual output by default is “quiet splash”, while in most cases the grub menu is initially hidden. This is often the case when there is only one Linux distribution installed on a computer, so inexperienced users may have no idea how to access grub’s options to change the kernel boot parameters. To do this, you can simply hold the “Shift” key once the splash screens appears. This should take you to the grub menu from where you may choose a kernel option. Depending on the grub settings,...

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I've had similar issues on one particular (Supermicro) motherboard, and while Steve's suggestion of using a text file works, there's a bit more nuance. I've tried to document the process below:

If you don't have bcfg available, you first need to get a copy of an EFI 2.x shell. The motherboard firmware probably has 1.x. The Arch wiki has more details, but for most 64-bit modern systems you'll want to grab the Shell.efi from here and rename it shellx64.efi and place it directly in the root of your EFI System Partition. If your motherboard provides a Launch EFI Shell from filesystem device, use it. Otherwise, you can use the built-in shell to launch the updated shell. See the wiki for further information.

Once you're in the 2.x shell, you'll want to make sure your boot option exists. You can list options with bcfg boot dump -b (the -b enables the pager, like more). If it does not exist, you'll need to add one, preferably to the top of the list. You can browse around -...

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There are three ways to pass options to the kernel and thus control its behaviour:

When building the kernel. See Kernel Compilation for details. When starting the kernel (usually, when invoked from a boot loader). At runtime (through the files in /proc and /sys). See sysctl for details.

This page explains in more detail the second method and shows a list of the most used kernel parameters in Arch Linux.

Not all parameters are always available. Most are associated with subsystems and work only if the kernel is configured with those subsystems built in. They also depend on the presence of the hardware they are associated with.

Parameters either have the format parameter or parameter=value.

Note: All kernel parameters are case-sensitive. Most of them are lower case, writing those in upper case does not work.

Configuration

Kernel parameters can be set either temporarily by editing the boot menu when it shows up, or by modifying the boot...

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Question:

I need to add the boot parameter foo=bar to my kernel. How can I do this once for testing, and permanently if testing was a success?


Solution:1

To temporarily add a boot parameter to a kernel:

Start your system and wait for the GRUB menu to show (if you don't see a GRUB menu, press and hold the left Shift key right after starting the system). Now highlight the kernel you want to use, and press the e key. You should be able to see and edit the commands associated with the highlighted kernel. Go down to the line starting with linux and add your parameter foo=bar to its end. Now press Ctrl + x to boot.


To make this change permanent:

From a terminal (or after pressing Alt + F2) run:

gksudo gedit /etc/default/grub

and enter your password.

Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT and append foo=bar to its end. For example:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash...
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