U盘安装redhat 必须插入u盘才启动解决方法

最近还有很多网友反映使用u盘安装Red Hat Enterprise 5.4之后，把u盘拔下，不能引导linux. 其实就像  "使用u盘安装Red Hat Enterprise 5.4（需要u盘引导问题）" 所说：grub安装在sdb（u盘）而不是sda（硬盘）
我研究了很久，想想能不通用从u盘启动red hat ,然后使用grub-install 重新安装grub。
过程如下：
1.把u盘插入，引导red hat
2.执行修复：
[root@localhost ~]# grub-install  /dev/sda
Installation finished. No error reported.
This is the contents of the device map /boot/grub/device.map.
Check if this is correct or not. If any of the lines is incorrect,
fix it and re-run the script `grub-install'.
# this device map was generated by anaconda
(hd1)     /dev/sdb
(hd0)     /dev/sda
3.修改grub.conf, 把(hd1,0)改为hd(0,0)
[root@localhost ~]# cat /boot/grub/grub.conf
# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/hda3
#          initrd /initrd-version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux Server (2.6.18-194.el5)
root (hd0,0)
kernel /vmlinuz-2.6.18-194.el5 ro root=LABEL=/ rhgb quiet
initrd /initrd-2.6.18-194.el5.img
title Other
rootnoverify (hd0,3)
chainloader +1
注意：kernel /vmlinuz-2.6.18-194.el5 ro root=LABEL=/ rhgb quiet，如果采用逻辑卷，显示类似这样:
kernel /vmlinuz-2.6.18-238.el5 ro root=/dev/VolGroup00/LogVol00
上面kernel 参数由系统安装时候设置，无需更改。
4.修改之后，关机，拔掉u盘，启动计算机。