How to install Grub from a live Ubuntu cd.

[granny4linux]

Catlett, thank you so much for this very helpful guide. I was able to reinstall my Grub without a hitch following your "How To".

[diebels]

This will restore grub if you already had grub installed but lost it to a windows install or some other occurence that erased/changed your MBR so that grub no longer appears at start up or it returns an error.

Using the feisty live-cd, my chroot had no hardisk devices in /dev,
so what i did was something like this:

sudo -s
mkdir /target
mount /dev/sda2 /target
mount --bind /dev /target/dev
mount --bind /proc /target/proc
mount --bind /sys /target/sys
chroot /target
grub-install /dev/sda

[Azakus]

Using the feisty live-cd, my chroot had no hardisk devices in /dev,
so what i did was something like this:

sudo -s
mkdir /target
mount /dev/sda2 /target
mount --bind /dev /target/dev
mount --bind /proc /target/proc
mount --bind /sys /target/sys
chroot /target
grub-install /dev/sda

Yes. This is what I had to do last time.

[kubobbu]

Catlett... thanks for your response, and thanks also to those who added additional comments.

I ran the procedure outlined, closed the terminal, and exitied the live CD. Then rebooted the computer, and got Grub Error 18 again, so I guess the bios still can't find Grub to load the kernal.

I guess I'll have to reinstall, but I need someone to give me the partition information that will be needed so that the boot ends up in the right place... the first cylinders on the disk so it can be found.

Thanks!

[maccawolf]

Catlett,
I want to say thank you, cos I also lost my mountpoint for Grub, and following your instructions I was able to re point to it.

THANK YOU!

[micfreedom]

Sorry to butt in this lengthy article on GRUB.
I made a mistake in the partioning program. In GParted I clicked on "reboot from external drive".The program downloaded my booting program. But then I made the mistake in partitioning the External hard drive again!. This time, obviously, the booting program is not in the external hard drive any more. So The bootloader tried in vain to reboot.
I constantly come up0 with the error Grub stage 1.5 error 21.

I have changed the CMOS to read type = user, LBA Mode=on, P10 Mode= auto, Primary slave = Auto
yet, I still cannot by apss error 21.


I did go into Ubuntu terminal on the Live CD. When I tried find /boot/grub/stage1
it said "cannot find"
So I am with a blank screen and error 21 (I write this from my wife's computer!)

[n8bounds]

Once again these forums gave me exactly what I needed. Thanks guys!

[barcaxi]

Thank you.

I tried to install Ubuntu 7.04 to a external USB disk and subsequently got the error message at boot time:-

GRUB loading stage1.5
GRUB loading, please wait...
Error 21


The commands mentioned above (and listed below) fixed my grub setup. Thanks!


$ sudo grub
grub>find /boot/grub/stage1
(hd0,0) # a old Debian version
(hd0,2) # the existing Ubuntu version I want to recover

grub>root (hd0,2)

grub>setup (hd0)

grub>quit

$ sudo reboot # Grub works again!!

[doubledave]

wow, i just wanted to post how appreciative i am!

this worked for ubuntu moron numero uno (me)-

i had wiped my kubuntu partition after having problems with ubuntu (feisty), and my boot screen was big time effed.

got grub looking back to normal, which is a huge relief.

now off to try to fix one of my other huge mistakes...

[ArchangelUriel]

Good morning from Greece... Well, as most ppl who read this thread, I had a working dual-boot systmem with Ubuntu Feisty and Windows XP. Unfortunately I had to format my Windows partition and reinstall them. So there goes the GRUB... Since I do not want just to reinstall Ubuntu but only to get GRUB working I followed your instruction and here is what i got...

ubuntu@ubuntu:/$ sudo mkdir /mnt/root
ubuntu@ubuntu:/$ sudo mount -t ext3 /dev/sda5 /mnt/root
ubuntu@ubuntu:/$ sudo mount -t proc none /mnt/root/proc
ubuntu@ubuntu:/$ sudo mount -o bind /dev /mnt/root/dev
ubuntu@ubuntu:/$ sudo chroot /mnt/root /bin/bash
root@ubuntu:/# grub
Probing devices to guess BIOS drives. This may take a long time.

       [ Minimal BASH-like line editing is supported.   For
         the   first   word,  TAB  lists  possible  command
         completions.  Anywhere else TAB lists the possible
         completions of a device/filename. ]
grub> find /boot/grub/stage1
find /boot/grub/stage1
 (hd0,5)
grub> root (hd0,5)
root (hd0,5)
grub> setup (hd0)
setup (hd0)
 Checking if "/boot/grub/stage1" exists... yes
 Checking if "/boot/grub/stage2" exists... yes
 Checking if "/boot/grub/e2fs_stage1_5" exists... yes
 Running "embed /boot/grub/e2fs_stage1_5 (hd0)"...  17 sectors are embedded.
succeeded
 Running "install /boot/grub/stage1 (hd0) (hd0)1+17 p (hd0,5)/boot/grub/stage2 /boot/grub/menu.lst"... failed

Error 22: No such partition
grub>

Trying to see what is going wrong I tried "fdisk -l". Here is the result.

root@ubuntu:/# fdisk -l
omitting empty partition (5)

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1         510     4096543+  12  Compaq diagnostics
/dev/sda2   *         511       17219   134215042+   7  HPFS/NTFS
/dev/sda3           17220       19457    17976735    5  Extended
/dev/sda4           19333       19457     1003968   82  Linux swap / Solaris
/dev/sda5           17220       19332    16972609+  83  Linux

Disk /dev/sdb: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       30401   244196001    c  W95 FAT32 (LBA)
root@ubuntu:/#

I think heri0n had the same problem.... So is there any way to recover GRUB, or should I format the disk and start over?

Thank you in advance

Archangel Uriel