参考：
《鸟哥的Linux私房菜》第26章
http://hi.baidu.com/wg_wang/item/f9375c2f00ca75c0ee10f1db
http://www.linuxdiyf.com/bbs/thread-193762-1-1.html
环境：
Wind7主机+Debian6虚拟机，虚拟机软件是VirtualBox
第一步、下载Linux源码
首先需要看一下当前Linux使用的版本
pengdl@debian:~$ uname -r
2.6.32-5-686
可以看到，当前使用的Linux内核版本是：2.6.32.5
为了说明问题，我们也从网上下载linux-2.6.32.5（当然也可以下载最新的版本，但是有风险）。下载地址如下：
ftp://ftp.kernel.org/pub/linux/kernel/v2.6/
我下载的是：linux-2.6.32.5.tar.xz
第二步、解压Linux内核
将来把内核源码解压到/usr/src/kernels下
mkdir -p /usr/src/kernels
tar -xJf linux-2.6.32.5.tar.xz -C /usr/src/kernels/
第三步、编译Linux内核
清理垃圾：
cd /usr/src/kernels/linux-2.6.32.5
make mrproper
make clean
编译内核前需要配置，为了说明问题，直接将本机自带的配置config-2.6.32-5-686拷贝到刚才解压的目录下(如果下载了比较新的内核，就需对照着config-2.6.32-5-686自己配置了)，并重命名为.config
cp /boot/config-2.6.32-5-686 /usr/src/kernels/linux-2.6.32.5/.config
cd /usr/src/kernels/linux-2.6.32.5
make menucongfig
修改General setup内的Local version为pengdl，目的是防止执行make install和make modules_install的时候跟旧的发生冲突。
make bzImage -j4
make modules -j4
make modules_install
make install
制作initrd镜像
mkinitramfs 2.6.32.5pengdl -o /boot/initrd.img-2.6.32.5pengdl
其中2.6.32.5pengdl 就是执行完make modules_install后，在/lib/modules下新生成的文件夹
此时/lib/modules和/boot下的内容如下（其中带有686的是系统原先就有的，带pengdl的是我们新生成的，
其中之所以有以.old结尾的文件，是因为执行了两次make install，实际上执行一次就行了。手动将*.old删除）：
debian:/usr/src/kernels/linux-2.6.32.5# ls /lib/modules/
2.6.32-5-686 2.6.32.5pengdl
debian:/usr/src/kernels/linux-2.6.32.5# ls /boot/
config-2.6.32-5-686 System.map-2.6.32-5-686
config-2.6.32.5pengdl System.map-2.6.32.5pengdl
config-2.6.32.5pengdl.old System.map-2.6.32.5pengdl.old
grub vmlinuz-2.6.32-5-686
initrd.img-2.6.32-5-686 vmlinuz-2.6.32.5pengdl
initrd.img-2.6.32.5pengdl vmlinuz-2.6.32.5pengdl.old
debian:/usr/src/kernels/linux-2.6.32.5#
第四步、更新grub
grub-mkconfig >/boot/grub/grub.cfg
可以看看新生成的grub.cfg的内容：
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#
### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
load_env
fi
set default="2"
if [ "${prev_saved_entry}" ]; then
set saved_entry="${prev_saved_entry}"
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
set boot_once=true
fi
function savedefault {
if [ -z "${boot_once}" ]; then
saved_entry="${chosen}"
save_env saved_entry
fi
}
function load_video {
insmod vbe
insmod vga
insmod video_bochs
insmod video_cirrus
}
insmod part_msdos
insmod ext2
set root='(hd1,msdos5)'
search --no-floppy --fs-uuid --set 87115ddc-75d2-4f74-b8c4-e3796e6a244a
if loadfont /share/grub/unicode.pf2 ; then
set gfxmode=640x480
load_video
insmod gfxterm
fi
terminal_output gfxterm
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
set locale_dir=($root)/boot/grub/locale
set lang=en
insmod gettext
set timeout=5
### END /etc/grub.d/00_header ###
### BEGIN /etc/grub.d/05_debian_theme ###
insmod part_msdos
insmod ext2
set root='(hd1,msdos5)'
search --no-floppy --fs-uuid --set 87115ddc-75d2-4f74-b8c4-e3796e6a244a
insmod png
if background_image /share/images/desktop-base/spacefun-grub.png; then
set color_normal=light-gray/black
set color_highlight=white/black
else
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
fi
### END /etc/grub.d/05_debian_theme ###
### BEGIN /etc/grub.d/10_linux ###
menuentry 'Debian GNU/Linux, with Linux 2.6.32.5pengdl' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32.5pengdl ...'
linux /boot/vmlinuz-2.6.32.5pengdl root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32.5pengdl
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32.5pengdl (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32.5pengdl ...'
linux /boot/vmlinuz-2.6.32.5pengdl root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32.5pengdl
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-686' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32-5-686 ...'
linux /boot/vmlinuz-2.6.32-5-686 root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-5-686
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-686 (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32-5-686 ...'
linux /boot/vmlinuz-2.6.32-5-686 root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-5-686
}
### END /etc/grub.d/10_linux ###
### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###
### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###
### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###
### BEGIN /etc/grub.d/41_custom ###
if [ -f $prefix/custom.cfg ]; then
source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
其中已经有了我们新添加的内核了：
### BEGIN /etc/grub.d/10_linux ###
Found linux image: /boot/vmlinuz-2.6.32.5pengdl
Found initrd image: /boot/initrd.img-2.6.32.5pengdl
menuentry 'Debian GNU/Linux, with Linux 2.6.32.5pengdl' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32.5pengdl ...'
linux /boot/vmlinuz-2.6.32.5pengdl root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32.5pengdl
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32.5pengdl (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32.5pengdl ...'
linux /boot/vmlinuz-2.6.32.5pengdl root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32.5pengdl
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-686' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32-5-686 ...'
linux /boot/vmlinuz-2.6.32-5-686 root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-5-686
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-686 (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32-5-686 ...'
linux /boot/vmlinuz-2.6.32-5-686 root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-5-686
}
### END /etc/grub.d/10_linux ###
如果按照上面的配置，启动时，Linux 2.6.32.5pengdl 会放在第一个，如果不手动按上下键进行选择，那么启动的将是我们刚编译出来的内核，如何让系统默认启动旧的内核呢？这里有几种方法：
1、手动修改grub.conf，交换旧内核和新内核的位置：
### BEGIN /etc/grub.d/10_linux ###
menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-686' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32-5-686 ...'
linux /boot/vmlinuz-2.6.32-5-686 root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-5-686
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-686 (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32-5-686 ...'
linux /boot/vmlinuz-2.6.32-5-686 root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32-5-686
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32.5pengdl' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32.5pengdl ...'
linux /boot/vmlinuz-2.6.32.5pengdl root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro quiet
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32.5pengdl
}
menuentry 'Debian GNU/Linux, with Linux 2.6.32.5pengdl (recovery mode)' --class debian --class gnu-linux --class gnu --class os {
insmod part_msdos
insmod ext2
set root='(hd0,msdos1)'
search --no-floppy --fs-uuid --set 2c7658ba-7c5c-45f2-8117-d70fcadcdda6
echo 'Loading Linux 2.6.32.5pengdl ...'
linux /boot/vmlinuz-2.6.32.5pengdl root=UUID=2c7658ba-7c5c-45f2-8117-d70fcadcdda6 ro single
echo 'Loading initial ramdisk ...'
initrd /boot/initrd.img-2.6.32.5pengdl
}
### END /etc/grub.d/10_linux ###
2、或者，修改 set default="0" ，将0改为2。直接在这里改，如果再更新grub.conf，default的值又变为了0，其中在grub.conf的最上面给出了方法：
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#
我们应该修改/etc/default/grub这个文件，将GRUB_DEFAULT=0 改为GRUB_DEFAULT=2，然后重新执行
grub-mkconfig >/boot/grub/grub.cfg
下面是启动测试：（可以用上下箭头选择有启动的内核）
注意：
因为我是用的是VirtualBox虚拟机，更新完内核后，需要重新安装VirtualBox增强工具，增强工具的安装方法参见：
http://www.cnblogs.com/pengdonglin137/p/3366765.html#a8
安装增强工具的时候，会把上次安装的增强工具给删掉。
完！！