GRUB CD image and Error 15

This is a post for anyone who, like me, has been doing web searches to find out what might be the problem if your Linux machine displays GRUB Error 15 on booting. Or who has general GRUB issues to debug.

My problem was Error 15, which indicates that GRUB cannot find one of the files it needs. If you get it while setting up GRUB, it’s often fairly easy to find out what’s wrong. But if GRUB thinks it’s installed OK, and you then reboot, you can still get this message but without any further information to help you debug it.

To cut a long story short, the issue for me was that the BIOS (and GRUB while booting), saw my two hard disks in a different order from the way the kernel saw them after booting. So my assumptions that /dev/sda was the same as (hd0) was invalid.

Finding this out took a very long time, though, because, for reasons too complex to go into here, I was booting this server not from a regular CD but from an emulated CD the other side of the Atlantic.

Things became a lot faster when I found this section in the GRUB documentation which explained how to make a bootable CD ISO image with GRUB on it. To save you the trouble, here’s one:

I could mount this and use the GRUB console command line to find out what was wrong. It’s worth exploring the GRUB console, if you haven’t already. It can do things like filename completion when you press TAB, and can even display the contents of text files using, for example,

cat (hd0,0)/boot/grub/menu.lst

In my case I found that the BIOS of the machine allowed me to choose the boot order of the hard disks, and swapping them there was the easiest solution.

Hope this is useful to somebody!

5 Comments

Hi Quentin

You may remember, but you wrote and opinion piece for me, on XML, when I was features editor of the IEE’s members’ magazine.

I’m retired now – sort of – I edit a magazine two days a week – firmly committed to Linux, in my case Ubuntu 6.06. I’ve just acquired a new spare PC, in case the other one fails at a awkard moment, and I’ve been trying to install 6.06. I thought it would be a doddle, but I’ve run into Error 15 problems and just don’t know what to do.

I started by putting a a fresh copy of 6.06 into the DVD drive. All went well at first, the live CD worked fine, so I opted for installation. About 80% of the way through, I got the message, “sorry, but installation has failed”. I’ve never seen that before. I tried again, you never know, but got the same result.

Thinking their might be a problem with the installation CD, I tried the DVD that comes with Ubuntu Unleashed. This produced the following:

GRUM Loading stage 1.5
GRUB loading please, wait…
Error 15

When I went back and tried the installation CD I got exactly the same result.

My only thought is that, in some way, I’ve got a faulty boot loader, and all I can think of is to take the machine back to the people who built it for me, and ask them to clean-up the hard disk.

Any other ideas?

Best regards

Roger Dettmer

Read your article last night whilst trying to divulge a similar problem.

grub had put hd1,0 in my menu.lst file (which was right according to the layout of my drives). However incorrect when trying to boot from Grub. I changed this to hd0,0 and magically everything worked!

Thanks for the heads up on your article!

This is a short note to thank you for your original post above.

I started out this day with one important chore on my to-do list – to back up my Linux system. To my perplexment (is this a word ?), when I tried to boot the machine, it responded with the same symptoms you described – the grub error 15.

Booting with a recovery CD, I could not find anything out of the ordinary or even suspect in the root/boot area on my main disk. In total frustration, I googled and was rewarded with a hit on your 1/7/2007 post here. Your solution proved to be precisely the one I needed to reboot my machine.

The “rest of the story”, if anyone is interested, is that I backup on an external disk. This day, I had powered up the backup housing before I booted the system (maybe I have never done this before). This sequence must have confused my BIOS into changing the boot order to one that it thought was appropriate, i.e., boot the backup first. After understanding the confusion (from reading your post), I now have two ways to fix the problem – 1. power up the backup after booting, or 2. changing the boot order in BIOS.

Thanks a million – You deserve credit for an excellent research effort!

JWalls

Hey
Just another thank you

Just what I needed

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