In section 2 above I mentioned you can download a new kernel from ftp://ftp.kernel.org/ However, this site is often too busy to get through and the maintainers of this site encourage you to download the kernel from a location near you. You can access a mirror site by going to ftp://ftp.<country code>.kernel.org/ (like ftp.ca.kernel.org).
arch/<cpu>/boot/bzImagefile to the
/bootdirectory (or some place else if your Linux system uses a different convention where kernel images and the like are stored)
/boot/bzImagefile to something like
/etc/lilo.conffile and go to the LFS section
lfskernel(or whatever you've named the originally called bzImage file)
liloto update the boot loader.
Copy the entire source tree of the new kernel to $LFS/usr/src. This
can easily be accomplished by running
cp -av <kernel directory> $LFS/usr/src
Often the /usr/local/include/linux directory is a symlink to /usr/src/linux and /usr/src/linux is often a symlink to /usr/src/<kernel version>. Make sure that /usr/src/linux now points to directory of the kernel source that you have unpacked before.
It's possible that on your system /usr/include/linux points to /usr/src/linux - this depends on your distribution.
Execute the following commands to create the proper symlinks on the LFS system.
Please note that if you need to compile software that's going to be used on your normal Linux system and it needs the kernel headers, it might be a better idea to restore the symlinks back into their original position if you decide not to load the new kernel for the normal Linux system. It is perfectly safe to load the lfskernel for both the LFS system and the normal system.
Reboot your system and start your LFS system. Verify that the newly installed kernel doesn't perform out-of-the-ordinary actions (like crashing).