How (& Why) To Install i686 Kernel In Fedora Core 6 in 7 Steps

Anaconda has a well documented defect where it installs i586 based kernel in i686 machines. It causes problems with several drivers including nvidia drivers. Also you will gain performance improvement by moving to i686 kernel. Let's upgrade the kernel in just 7 steps.

First you must verify that you do have a i686 cpu and you have i586 kernel.

Note: All the following commands must be run as root.

1. Run the following from terminal to know your cpu architecture:
arch

2. Now run the following to find out the kernel installed:
yum list kernel

You may get something like this at the end:
kernel.i586 2.6.18-1.2798.fc6 installed
Note the i586. It shows that you have the wrong kernel installed. Let's go to the next step.
Note: If it shows i686 then you needn't proceed further.

3. First save a copy of your grub.conf. You may need it.
cd
cp /boot/grub/ .

4. Next remove the existing kernels.
yum remove kernel
Confirm the removal.
This will remove the kernel and all iuts dependencies. Note the dependencies.You will have to install them later.

You may get a grub error message like:
grubby fatal error: unable to find a suitable template
grubby: doing this would leave no kernel entries. Not writing out new config.

Ignore it.

5. Now install the i686 kernel:
yum install kernel.i686
This will force installation of i686 kernel. Confirm the installation when asked.

You may get grub error like this:
grubby fatal error: unable to find a suitable template

This one is dangerous. If you get it then first fine the exact version of kernel installed as follows:
yum list kernel
You will get a version string like: 2.6.20-1.2933.fc6
Write it down.
Then open grub.conf in any text editor like gedit. I did:
gedit /boot/grub/grub.conf &
Note the line starting with kernel /vmlinuz. Change the version string of vmlinuz to the string you copied before. Double check to ensure there are no typos. Then repeat the process for the line starting with initrd /initrd. Save the file and exit.

6. Now install the dependencies you removed earlier. I did the following:
yum install compiz gnome-volume-manager systemtap gnome-session pcmciautils

7. Reboot and you are done:
reboot

Note: You may get an error while rebooting if you previously ignored the "unable to find suitable template" error or incorrectly modified grub.conf. You will get a second chance to modify it now to make it boot. However if you do have to modify then ensure that you make the same changes in grub.conf so you don't have to type it again and again while rebooting.