HOWTO: Restore GRUB (if your MBR is messed up)

[Tass]

You know, some times I could kick myself.

Thank you very much for you help - it was driving me insane!!

[nomorewin]

Hi guys,
The problem I'm having is that Ubuntu installed GRUB onto /hdb1, but my primary partition (as far as my BIOS is concerned) is /sda1
I can run 'grub' and reinstall grub like described by remmelt, but I don't know what the ID of /sda1 is. (hd1,0)? (hd2,1)? What command can I use to get the mapping?
I'm able to boot off the Live CD only at the moment.

Rikko, I think you want to execute the following:

# sudo grub
[ 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
(hd0,0)

grub> quit


Regards.

[shabuntu]

I have fedora 8. I tried installing Ubuntu by formatting the partition used for fedora. Installation aborted saying grub-install failed and it's fatal error. Then I rebooted my laptop to see only "GRUB" without any menu option like before (fedora and vista). I again installed fedora 8 to restore it. Now I want to install ubuntu. What should I do get avoid this install issue?

[BobSongs]

Super Grub Disk worked easily and well to reinstall (restored) GRUB which allowed my abiltiy to have either Ubuntu or Kubuntu session or the boot windows XP.

I googled for Super Grub Disk, D/L ISO, burned CD, booted from CD and followed the simple guided directions. It worked easily.

I tried using the live CD and the Grub command but it did not work for me (find /boot/grub/stage1 generated error message).

I tried the mkdir ubuntu method, mount /dev/hdb, chroot ubuntu method and it did not work (got stuck on grub-install /dev/hda step).

Super Grub Disk was elegantly simple and effective.

I'm going to give Super Grub Disk a try.

VNBuddy2002 - FYI: The Ubuntu Feisty Fawn 7.04 Live CD and Alternative setup CDs do not comply with this tutorial. The Breezy Badger CD did the very thing you describe but Feisty does not.

I have some of suggestions:

1. Please keep your tutorial updated and accurate.
   
2. Ensure this technique works with the various active Ubuntu versions (such as Gutsy, Feisty, Edgy and Dapper). This gives us an accurate picture. It avoids 1) the unnecessary slogging through 17-odd pages of questions and answers to tease out a solution; 2) ending up in a state where the user is unprepared to handle a crisis. (I have a 2nd PC so it's not urgent for me. But not everyone has this luxury.)
   
3. Include links to useful utilities in your main post such as the Super Grub Disk mentioned in the text above. This appears to be (though not yet tested, it soon will be) an excellent way to get folks out of a bind if they don't have a setup CD that works with your described message. And for many Ubuntu users: a messed-up GrUB is a fairly serious problem.
4. If you'd rather not maintain this tutorial delegate it to someone else. I'm sure someone would be glad to put something together that's accurate and up-to-date.
   

I do thank you for the effort. But I must admit: my appreciation could be much higher. Forgive the obvious frustration, but the subject matter you've written about is very important. The lack of accuracy could be dealt with.

[BobSongs]

Well. Super Grub Disk worked just fine.

I used the floppy disk .img file, but there's also a CD-ROM ISO.

First I formatted the diskette. Then I used the dd command to move it to the diskette. Then I booted to the fd0 (diskette) drive.

When the menu came up I selected choice #2.

Within seconds my Grub boot menu appeared in color. Nice. Not how I remember it, but nice none-the-less.

I selected Ubuntu as a boot choice, shut down and removed the diskette. When I restarted Grub was completely restored and normal.

Thanks again, dolecannery, for the tip.

[KingdomKid]

Hey guys, I recently cloned my hard drive with Acronis. Every thing worked ok except that I can not boot into windows anymore on the new cloned drive. I have a dual boot system (Kubuntu / Windows XP Pro).
I can boot into Kubuntu fine and all is well. Just booting into XP is messed up.

When I choose to boot into XP it just sits there with "starting up" in the top left of the screen.

I was wondering if doing the steps at the beginning of this post is what I need to do?

Does anyone know what got messed up during the cloning process and how to fix it so I can get back into my XP side?

[StGeorge]

The more I read about grub the more my head gets messed up.
Why on earth does grub automatically install to the MBR?
I have not been able to fix grub for 6 months now.
I have been here and there trying out Super Grub Disk, XUbuntu Restore, Live CD to mention just a few.
If it wasn't for PQ Boot Magic rescue disk my windows system would be unreachable.
Grub is a messy boot loader.
I have a simple problem but no one seems to have any idea how to solve it.
My 98se is on a dedidated 10gb drive. C
My Ubuntu is on the first section of a second HD
It is called hdb1.
So why will grub not install itself there?
I was going to enclose a copy of my Menu.lst.
I have just found out that EXPLORE2FS.EXE does not work now either.
Anyway just a vein hope someone will know what to do.

[StGeorge]

Oh well I deciced to re install instead.
That is another suprising thing.
I did have 6.06 installed.
Decided to re install with 7.10.
It would not keep any files or settings.
None of the previous programs either.
I had to format the old installation prior to re installation.
Luckily I had used Explore2fs to get any files or folders I wanted transfered to windows.

Right at the end of installation there is an advanced button.
On clicking it it gave me the option where to install grub.
I chose (hd1,1) on the second occassion.
So at long last I have grub installed where I want it.
Personally I think that anyone not having much experience with Linux having trouble with grub should simply re install the OS.
I must have spent about 5 to 10 working days trying to fix grub over 6 months. Re installation, 2 hours.
(I had to re install twice as my Ubuntu drive is called sdb1 or hd1,1. Why name a drive twice?).
I am all for a learning curve but a learning circle messes up my head.

[rare HERO]

Restore GRUB quite simple in Ubuntu, instead going through all the "gain root access" and play with shell commands, you can use the Ubuntu installation CD to restore it without going through all kinds of hassles.

Here are the steps:

1. Boot your computer up with Ubunto CD
2. Go through all the process until you reech "[!!!] Disk Partition"
3. Select Manual Partition
4. Mount your appropriate linux partions

/
/boot
swap
.....

5. DO NOT FORMAT THEM.
6. Finish the manual partition
7. Say "Yes" when it asks you to save the changes
8. It will give you errors saying that "the system couldn't install ....." after that
9. Ignore them, keep select "continue" until you get back to the Ubuntu installation menu
10. Jump to "Install Grub ...."
11. Once it is finished, just restart your computer

Good luck!.

Doesn't work.
after step 5 i get this:

The file system on /dev/hdb1 assigned to / has not been marked for formatting. File systems used by the system (/, /boot, /usr, /var) must be reformatted for use by this installer. Other file systems (/home, /media/*, /usr/local, etc.) may be used without reformatting.

Won't allow me to continue.

[rare HERO]

From the grub prompt trying using the <tab> key to see what choices you have.

grub> root (<tab>

Tomy

I get this:

grub> root
Error 1: Filename must be either an absolute pathname or blocklist