Using the Ubuntu Desktop/Live CD
Overwriting the Windows bootloader
This will overwrite your Windows Boot Loader. It is OK to do this, in fact that is the goal of this how to (in order to boot Ubuntu).
Boot from a Live CD and open a terminal. You'll need to run a few commands as root so you can use sudo -i to get a root shell and run them normally instead of using sudo on each of them. Be extra careful when running a root shell, especially for typos!
We'll need to find which partition your Ubuntu system is installed on. Type the command fdisk -l. It will output a list of all your partitions, for example :
fdisk -l
Disk /dev/hda: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 1 8 64228+ 83 Linux
/dev/sda2 9 1224 9767520 83 Linux
/dev/sda3 * 1225 2440 9767520 a5 FreeBSD
/dev/sda4 2441 14593 97618972+ 5 Extended
/dev/sda5 14532 14593 498015 82 Linux swap / Solaris
/dev/sda6 2441 14530 97112862 83 Linux
Partition table entries are not in disk order
Here I have three Linux partitions. /dev/sda2 is my root partition, /dev/sda1 is my /boot partition and /dev/sda6 is my /home partitions. If you only have one, obviously this is the one your Ubuntu system is installed on. If you have more than one and you don't know which one your Ubuntu is installed on, we'll look for it later. First, create a mountpoint for your partition, for example :
mkdir /media/root
Then mount your partition in it. If you don't know which one it is, then mount any of them, we'll see if it's the correct one.
mount /dev/sda2 /media/root
Of course, replace /dev/sda2 with the correct name of your partition. You can check if it's the correct one by running ls /media/root, which should output something like this :
bin dev home lib mnt root srv usr
boot etc initrd lib64 opt sbin sys var
cdrom initrd.img media proc selinux tmp vmlinuz
If what you have looks not at all like this, you didn't mount the correct partition. Do umount /media/root to unmount it and try another one. You also need to mount your /boot partition if you made one, like this :
mount /dev/sda1 /media/root/boot
To make sure it was the correct one, run ls /media/root/boot, which should output something like this :
config-2.6.18-3-686 initrd.img-2.6.18-3-686.bak System.map-2.6.18-3-686
grub lost+found vmlinuz-2.6.18-3-686
initrd.img-2.6.18-3-686 memtest86+.bin
Once again, if what you have doesn't fit, unmount it and try another partition.
Now that everything is mounted, we just need to reinstall GRUB :
sudo grub-install --root-directory=/media/root /dev/sda
If you got BIOS warnings try:
sudo grub-install --root-directory=/media/root /dev/sda --recheck
Of course, replace /dev/sda with the location you want to install GRUB on. If all went well, you should see something like this :
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'.
(hd0) /dev/sda
Reboot (to your hard drive). Grub should be installed and both Ubuntu and Windows should have been automatically detected.
If, after installing grub, Windows does not appear in the boot menu you will need to edit /boot/grub/menu.lst (That is a small "L" and not the number 1 in menu.lst)
Open a terminal and enter :
gksu gedit /boot/grub/menu.lst
Or, in Kubuntu:
kdesu kate /boot/grub/menu.lst
Your Windows stanza should look something like this :
title Windows XP/Vista # Use any title you wish, it will appear in the grub boot menu
rootnoverify (hd0,0) # This is the location of the windows partition
makeactive
chainloader +1
Note: Put your Windows stanza before or after AUTOMAGIC KERNEL LIST in the menu.lst
Preserving Windows Bootloader
This method allows you to restore GRUB and keep the Windows bootloader as your primary bootloader. Thanks to Ubuntu's support for NTFS writing it's now an absolute cinch.
The method shown above puts GRUB back on the MBR (master boot record) of the hard drive instead of in the root partition. But you probably won't want that, if you use a third-party boot manager like Boot Magic or System Commander. (The original poster also suggested that this would be useful to restore the Grub menu after a re-ghosting.) In that case, use this alternative.
If you have your Linux system in a second (or third...) hard disk this method will not work. Please check Super Grub Disk's method that address this problem.
Restoring GRUB
1. Boot from a Live CD, like Ubuntu Live, Knoppix, Mepis, or similar. Ideally use Ubuntu 8.04 or higher as this has NTFS write support and makes life a bit easier; this isn't necessary, just handy.
2. Open a Terminal. Open a root terminal (that is, type "su" in a non-Ubuntu distro, or "sudo -i" in Ubuntu). Enter root passwords as necessary.
3. Type "grub" which makes a GRUB prompt appear.
4. Type "find /boot/grub/stage1". You'll get a response like "(hd0)" or in my case "(hd0,3)". Use whatever your computer spits out for the following lines. Note that you should have mounted the partition which has your Linux system before typing this command. (e.g. In Knoppix Live CD partitions are shown on the desktop but they're not mounted until you double-click on them or mount them manually)
5. Type "root (hd0,3)" note the space between root and (hd0,3).
6. Type "setup (hd0,3)". This is key. Other instructions say to use "(hd0)", and that's fine if you want to write GRUB to the MBR. If you want to write it to your linux root partition, then you want the number after the comma, such as "(hd0,3)".
7. Type "quit".
8. At this stage you can either restart the system and install your own bootloader, or you can continue and tell the Windows bootloader where to find GRUB which will handle booting Linux.
Making Windows Load GRUB (and then Linux)
1. In Linux open a command window.
2. Mount a drive which you can share with Windows; this could be a USB drive, a FAT32 partition on your machine, or if you are using a Linux distro which supports NTFS writing like Ubuntu 8.04+ (maybe earlier?) then you can mount the actual Windows c:\ drive itself! The big bonus of writing to the windows drive is that you are going to need to put a file there, so it saves copying a file around. For example
#mkdir /tmp/windows
#mount /dev/sda1 /tmp/windows
3. Now you are going to make a copy of your boot partition; finding what this is called is not 100% deterministic because Linux might call your drives sdX or hdX, whereas GRUB always calls them hdX and Linux names them [hd|sd][Letter][Number] whereas GRUB names them as hd[Number][Number]; note that df won't work as you are booted from a live CD. But let's have a go; if you installed GRUB on (hd0,0), then /boot is on hda1 or sda1, (hd1,0) == hdb1 or sdb1, (hd0,1) == hda2 or sda2, etc... this narrows you down to two possibilities, now issuing ls /dev |grep hd will let you know if you have that drive on your machine, if nothing comes up which matches, then you must have an sd drive. OK, great...
4. Having hopefully determined your boot partition issue the command (as root)
#dd if=/dev/sda2 of=/tmp/windows/linux.bin bs=512 count=1
Where /dev/sda2 is your boot partition and /tmp/windows/ is the drive you want to copy the boot sector image to.
5. If you haven't created linux.bin in the Windows drive then you need to copy it there now.
6. Reboot into Windows, open c:\boot.ini in notepad, and on a new line at the bottom, add c:\linux.bin="Linux". This file might be write protected, if it is enable write in the right click context menu -> properties; you should disable write afterwards. Make sure that at the top of the boot.ini file there is a timeout set, i.e timeout=5. (Ah ha, you say, now I have NTFS support, why don't I just edit boot.ini in Linux, the answer to this is that Linux and Windows represent line breaks in different ways, so even though you can edit the file, it won't add a new line 残念)
7. That's it, reboot and you will be given the option of booting into Linux, selecting that will chainload GRUB and this will let you boot into your Linux distro.
From Inside Ubuntu
You have to run "grub" not from the Ubuntu Desktop/Live CD, but from your disk installation to make it work. To do this, mount your root partition (following examples assume a root partition on hda1):
sudo mkdir /mnt/linux
sudo mount /dev/hda1 /mnt/linux
then change directory to your installation sbin and run grub from there
cd /mnt/linux/sbin
sudo ./grub
Using the Unofficial "Super Grub Disk"
From within Windows
Double-click auto_super_grub_disk_1.0 icon, install it, and reboot.
On the next boot, select the UNetbootin-supergrubdisk menu entry; this will launch the Auto Super Grub Disk.
Do nothing till you see your Grub menu again.
- Next time you boot Windows, click yes when asked to remove UNetbootin-supergrubdisk to remove the Super Grub Disk menu entry.
As a standalone cd/floppy/usb
Preserving Windows Bootloader
The method shown above puts GRUB back on the MBR (master boot record) of the hard drive instead of in the root partition. But you probably won't want that, if you use a third-party boot manager like Boot Magic or System Commander. (The original poster also suggested that this would be useful to restore the Grub menu after a re-ghosting.) In that case, use this alternative.
This alternative, used without a third-party boot manager, will not cause Ubuntu to boot.
This alternative will let you boot your second hard disk Linux installations from Windows while the Using the Ubuntu Desktop/Live CD Preserving Windows Bootloader instructions will not.
Either:
- Burn into a cdrom (better) or a floppy
- Boot from it
Or:
- Run the installer and reboot when once done installing.
- On the next boot, select the "UNetbootin-supergrubdisk" menu entry; this will launch the Super Grub Disk interface.
Then:
Super Grub Disk (WITH HELP) :-)))
Select: your language
Select: Windows
Select: Windows chainloads Grub!
Select the Linux or Grub installation you want to restore to its own partition.
- You see the message: SGD has done it!
- Reboot
- You're done.
Using Microsoft Vista
If you have Vista installed and you installed Ubuntu and when you rebooted it didn't show up as a dual boot option, try going into Vista (since that is all you can do), use the program EasyBCD version 1.7
It looks like this:
Add your Linux install to the boot sequence.
Troubleshooting
This section applies to...
- Dual-boot setups in which Windows was installed after Ubuntu
- Conditions where Windows failure forced a re-installation
- Windows recovery techniques involving the "restoration" of the MBR
- Cases where GRUB failed to install
Prerequisites:
Preparing Your Working Environment
To begin the restoration procedure, insert your LiveCD and reboot your computer. Proceed with your LiveCD's bootup procedure until you are presented with an interface. If your LiveCD does not immediately present you with a console, also called a terminal, open one -- to do this with the Ubuntu LiveCD, click Applications -> System Tools -> Terminal.
Note: Since this is a LiveCD environment, any changes to user accounts or filesystem layouts at this level will not be permanent. This means you can set a temporary root password and create directories without affecting your actual installation.
Now, you need to gain root access. Under Ubuntu, this can be done with the following commands:
sudo -i
Under Knoppix, the following command will suffice, and you will not be prompted for a password.
su -
Now that you have root access, you need to mount the partition(s) containing your bootloader files.
You will need access to both your /sbin/ and /boot/ directories. If you have a /boot/ listing in your fstab, you are among those who will need to mount two partitions.
Begin by creating a mount point for your working environment -- you'll notice this is the same as creating a directory.
mkdir /mnt/work
If you need to mount /boot/, too, run the following command.
mkdir /mnt/work/boot
Now it's time to actually load your filesystem data. Review your fstab and identify the location(s) of / and /boot/; these will likely look something like /dev/hda3 and /dev/hda4, though the letter 'a' and the numbers 3 and 4 may differ.
Note: For the remainder of this howto, /dev/hda3 and /dev/hda4 will be assumed, so alter them as needed when typing them in yourself.
Enter the following commands to load your filesystem and some information GRUB may need.
mount /dev/hda4 /mnt/work
mount -o bind /dev /mnt/work/dev
mount -o bind /proc /mnt/work/proc
cp /proc/mounts /mnt/work/etc/mtab
Now, you have to enter your working environment. The following command will take care of that.
chroot /mnt/work/ /bin/bash
Warning: From this point on, any files you modify will affect your Ubuntu system. You have left the safety of the LiveCD. Exercise caution.
Recovering GRUB Automatically
If you have a separate /boot/ partition, type the following line.
sudo mount /dev/hda3 /boot/
Reinstalling GRUB from this point is easy. Just enter the following command.
sudo /sbin/grub-install /dev/hda
If the command you used above failed, which is unlikely, you will need to configure GRUB manually (it isn't too hard); if it succeeded, you should read the note at the start of the final section: "Configuring the GRUB Menu".
Recovering GRUB Manually
Before you can undertake the next step, it's important that you understand how GRUB identifies partitions.
To GRUB, numbers begin with 0, and letters are expressed numerically, also beginning with 0.
For example, /dev/hda1 is "hd0,0" to GRUB. Similarly, /dev/hdb3 is "hd1,2".
Note: The "root" line must point to the location of your /boot/ partition if you have one. If you do not have one, point it at your / partition.
sudo /sbin/grub
grub> root (hd0,2)
grub> setup (hd0)
grub> quit
Note: This step does not need to be done if you're just trying to recover your MBR. Installing Windows will not alter the contents of your existing menu.lst, so if everything was working right before, everything will continue to work right now, and you can restart your computer.
Open the GRUB menu file, /boot/grub/menu.lst, with your favourite text editor. An example follows.
sudo nano /boot/grub/menu.lst
Note: Your menu.lst file is used to control the operating systems GRUB displays on startup, as well as its visual appearance. This howto will only explain how to get your operating systems to boot; it will not tell you how to make your bootloader pretty.
A sample menu.lst, stripped of unnecessary comments, appears below. It is based on the /dev/hda3 and /dev/hda4 example above, and assumes Windows resides at /dev/hda1.
timeout 5 #The number of seconds GRUB should wait before booting an OS
default 0 #The entry which should be booted by default
fallback 1 #The entry which should be booted in the event of the first one failing
title Ubuntu, 2.6.10 #A 32-bit Ubuntu entry
#This (or something like it) should be in your configuration
root (hd0,2)
initrd /initrd.img-2.6.10-5-386
kernel /vmlinuz-2.6.10-5-386 root=/dev/hda4
title Ubuntu, 2.6.10 #Another 32-bit Ubuntu entry
#This is an example of an Ubuntu entry which does not have a separate /boot/ partition
#(it is provided only as an alternate to the example above -- do not use them together)
root (hd0,2)
initrd /boot/initrd.img-2.6.10-5-386
kernel /boot/vmlinuz-2.6.10-5-386
title Microsoft Windows XP Home #An entry for a Windows installation
#If you're reading this guide, you probably want this
root (hd0,0)
makeactive
chainloader +1
And that's it. Save and close the file, then reboot and try out the entries.
Using the Ubuntu Alternate/Install CD
This section explains how to rescue GRUB (the GRand Unified Boot loader), using the Ubuntu alternate/install CD ROM.
- Enter your computers BIOS to check computer can boot from CD ROM. If you can boot from CD, insert CD ROM into drive. Exit the BIOS (if needed save your settings to make sure the computer boots from the CD ROM).
When the Ubuntu splash screen comes up with the boot: prompt, type in rescue and press enter.
- Choose your language, location (country) and then keyboard layout as if you were doing a fresh install.
- Enter a host name, or leave it with the default (Ubuntu).
At this stage you are presented with a screen where you can select which partition is your root partition (there is a list of the partitions on your hard drive, so you are required to know which partition number Ubuntu is on). This will be dev/discs/disc0/partX, where the X is a partition number.
- you are then presented with a command prompt (a hash).
type $ grub-install /dev/hdaX where X is your Ubuntu root install.
The GUI Way: Using the Alternate/Install CD and Overwriting the Windows bootloader
- Boot your computer with the Ubuntu CD
- Go through the installation process until you reach "[!!!] Disk Partition"
- Select Manual Partition
- Mount your appropriate linux partitions:
DO NOT FORMAT THEM.
- Finish the manual partition
- Say "Yes" when it asks you to save the changes
- It will give you errors saying that "the system couldn't install ....." after that
- Ignore them, keep select "continue" until you get back to the Ubuntu installation menu
- Jump to "Install Grub ...."
- Once it is finished, just restart your computer
From:
http://doc.gwos.org/index.php/Restore_Grub and
http://ubuntuforums.org/showthread.php?t=76652
