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[FAQF] KC1: Won't boot
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rac
Bodhisattva
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Joined: 30 May 2002
Posts: 6553
Location: Japanifornia

PostPosted: Fri Nov 22, 2002 9:37 pm    Post subject: [FAQF] KC1: Won't boot Reply with quote

EDIT: This is the feedback thread for FAQ KC1: I made a mistake compiling my kernel and now my computer won't boot. What can I do now?.

Thanks for writing this: it's much more detailed than our original answer. A couple of points I'd like people to comment on:

For the section about booting from a backup kernel, it might be nice to have some brief instructions for folks using different bootloaders. Is it necessary to have a comment about the possibilities of conflicting modules in /lib/modules if you have two copies of the same kernel version installed?

Is it important to tell people not to panic? I often see newbies talking about reinstalling all of Gentoo when they run into this problem.

What do people think about the ordering of the first two options? I can definitely understand that the first option is faster and easier if the preparation has been done, and it definitely makes sense to be the first thing to think of in that case, but if somebody's totally new to kernel compilation, one could also make a case for having the instructions for booting from an install CD as the first thing. I think I'll leave the final call up to yokem55 on this one.
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Last edited by rac on Sat Nov 30, 2002 8:51 pm; edited 1 time in total
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yokem55
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Joined: 18 Apr 2002
Posts: 360
Location: Oregon

PostPosted: Sat Nov 23, 2002 4:49 am    Post subject: Reply with quote

Okay I edited it per your suggestions. However I don't have much experience in unsing Lilo at a nuts and bolts level (I had always let Mandrake do that for me), and from what I've read, Lilo doesn't support editing its config on the fly at boottime. So, I don't have much to add regarding other bootloaders. Any other suggestions are more than welcome.
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davejay
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Joined: 17 Mar 2003
Posts: 14

PostPosted: Mon Mar 24, 2003 10:25 pm    Post subject: Reply with quote

I'm glad you wrote this piece; unfortunately, it hasn't helped me.

I have been trying for two weeks to compile my first Gentoo kernel, with no success. In all cases, I get a kernel panic. I have combed through menuconfig over and over, reading as many lists as I can to find a solution, to no avail.

It occurs to me that a really helpful thing for someone like me (who apparently isn't selecting the correct menuconfig options for my machine) would be to take the .config file from the boot kernel on the CD, and use it as a starting point for a customized kernel. After all, if I can boot from the CD, but a kernel compiled using the same settings won't boot, I can rule out the settings as the problem, right?

Unfortunately, I have found no instructions on how to do this, or even any indication that the CD contains such a .config file. If it does, please consider putting information on how to load it into menuconfig as a reference for n00bs like myself. :)

-D
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Nooz
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Joined: 06 Apr 2003
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PostPosted: Sun Apr 06, 2003 2:09 pm    Post subject: I also get a Kernel Panic Reply with quote

I also get a Kernel Panic, mine is saying further that init could not be found.
I tried passing /sbin/init as boot agument... unsuccsessful.
I scanned my /dev for an entry named init... there was none.
So how the hell could i get that fixed?
Did I set wrong kernel conf?
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Svenr
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Joined: 28 Apr 2003
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PostPosted: Mon Apr 28, 2003 7:45 pm    Post subject: Making Kernel Backups for LILO Reply with quote

For those of you who want to use LILO and fear the compilation of an unbootable kernel, creating a backup boot configuration with LILO is really easy.

Step 1: You need a known bootable kernel. :) Compiling one is left as an excercise to the reader. ;)

Step 2: You have to backup this kernel. It is a good idea to leave this backup version within /boot. So this step boils down to:
cp /boot/known_booting_kernel /boot/backupped_kernel

Use the appropriate kernel filenames.

Step 3: Tell LILO about the backup.

Edit /etc/lilo.conf.
Copy the already existing part which boots your kernel. The gentoo installation manual section 23 "Configure a bootloader", subsection "Configuring LILO", tells you how this part is created, and it results in the following lines (example):

image=/boot/vmlinuz-2.4.20
label=linux
read-only
root=/dev/hda3

Copy all these lines and edit them to fit the new kernel. You have to edit the label line and the image line.

The label line should reflect the fact that this is a backup kernel, so make it say something like
label=linuxold

The image line is the path to the backupped kernel image instead of the soon to be compiled new one.

So you should end up having two almost identical sections (example):

image=/boot/vmlinuz-2.4.20
label=linux
read-only
root=/dev/hda3

image=/boot/vmlinuz-backup
label=linuxold
read-only
root=/dev/hda3


Step 4: Run /sbin/lilo to update the bootloader.

Lilo should report that it has added two configurations (at least - you might have additional boot configs for other OS as well) named linux and linuxold.

If you leave the other settings at their default, you have 5 seconds to decide which kernel you want to boot, the new one (label=linux) being the default which boots if no decision is made (because of the default=linux line - older versions of lilo made the first configuration the default one).


Note that you do not have to backup every new bootable kernel when you compile a newer one. The backup kernel is there to boot the system and allow you to recompile - not to be the second latest and greatest kernel version you compiled. So this job really has to be done only once to create the emergency boot.

If you like, you can from time to time add another backup version by adding another lilo.conf entry and a new kernel image file.

This mechanism worked for me on several versions of SuSE Linux and LFS. I hope this is useful for someone.

- Sven Rautenberg
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unixbhaskar
Tux's lil' helper
Tux's lil' helper


Joined: 29 Nov 2007
Posts: 85
Location: India

PostPosted: Sun Dec 30, 2007 11:22 am    Post subject: My new Installed gentoo in Compaq Laptop stuck everytime Reply with quote

When it boot in several palces.if it somehow mange to boot but login prompt showing way below the screen.I have compiled the right tarball and do all the necessary things as per the gentoo site.

I mean to say it sometime boot fast but the login prompt it stuck and and I have to physically reboot the system othertime

it at login prompt but I have to press enter serverral time to get the result on the screen.

I think some thing wrong with the display(I am not running X).At bootup time it says missing vesafb driver.I have nvidia card.It's a compaq presario V3000 laptop,which has openSUSE10.2 and RHEL in diffrent slices.

Any help wopuld be highly appreciated .

Thanks
Bhaskar :(
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