Last-ditch solutions for Grub Error 15

[FortyArc]

I installed Fedora 11 from DVD to my second hard drive (Windows XP is on the first). Ubuntu had been on the second hard drive previously and Fedora installed over it. When I tried to reboot after installing, Grub tossed up an Error 15.

Here are the solutions I have found on various forums, and the reasons why they aren't working for me.

1. Use Super Grub Disk to boot the computer and fix the boot record. I used Unetbootin on Windows to make a Super Grub USB key. When I try to boot with it I get a message that says "Could not find kernel image: vesamenu.c32" Apparently this is a known issue with Unetbootin on Windows. I don't have another way to make this disk because we only have Windows computers in the house.

2. Use the Windows Recovery Console and run the fixmbr command. My Windows installation has a known bug where the Recovery Console (which was not installed previously, so I have to run it from the Windows setup CD) doesn't acknowledge the administrator password.

3. Download the Windows setup floppies, which have a workaround for the password bug, and run Recovery Console. I have no floppy drive. I'm not sure if any computer in this house has a floppy drive. Guess I could buy one tomorrow, they're cheap. Maybe a USB floppy drive so that I can connect it to one computer and make the discs, then connect it to the other computer and use them.

4. Throw out the whole thing and reinstall Windows & Fedora from scratch in the proper order. I am very close to doing this, but since I have another computer I'll refrain for now. All of my important files are backed up (except for a couple of files that I created since the backup but then uploaded to the internet, so they're retrievable); anything else that was on the computer can be reinstalled if necessary.

Can anyone see anything that I'm missing or that I should try before #4?

[bob]

Have you tried this?

1. Boot off the DVD.
2. At the boot prompt type 'linux rescue'
3. The rescue mode will find the fedora installation
4. Type 'chroot /mnt/sysimage' (without quotes)
5. Type 'grub-install /dev/sda' (to install Grub to the MBR of the 1st HD)
6. Restart and you should get the boot menu

[FortyArc]

Boot from the Fedora DVD? I knew there had to be a way to rescue the boot record from there, but I didn't know what it was.

sda is my Windows hard drive; should I install Grub there or should I put it on sdb (the second hard drive where Fedora is at the moment)?

[bob]

Your machine has one mbr, which is currently run by Windows. Normally, you'd overwrite the mbr and Fedora would recognize and boot Windows off of a grub menu (shown as "other"). Not sure how you installed Ubuntu without overwriting it, but since you do have a problem with a Windows bug, if Windows is now booting, here's an option I've used before:

1). Unplug the Windows drive so that only the other drive is seen. Install Fedora as normal, with grub writing to the mbr of that drive.

2). Plug in the other drive and do a bios switch to boot from the Fedora drive first. It should boot Fedora but will ignore Windows. (Note: by switching the bios boot, you still should be able to boot Windows independently no matter what).

3). Sign into a terminal as root (su -) , give your password, and using a text editor such as 'gedit', do the following:

gedit /boot/grub/grub.conf

which will open a new window and show your current Fedora grub menu. Then add, to the bottom, something like this:

title Windows - Spawn Of The Devil (feel free to modify as necessary)
map (hd0) (hd1)
map (hd1) (hd0)
rootnoverify (hd1,0)
chainloader +1

So, that tells grub: "Hey, there's another drive...over there! Look at it and boot the first partition on it". You should get Windows booting.


So, since you've already done the Fedora install, you can do the first series of commands to overwrite the mbr, or do the "two drives, two mbrs" method to get things working without bothering Windows boot.ini or..... you can simply reinstall Fedora once more and allow it to overwrite the mbr of the first drive, where it really wants to be located.

[FortyArc]

Ubuntu installed a working Grub, which would let me choose between Windows and Ubuntu at startup. Installing Fedora over top of Ubuntu seemed to mess things up. Neither Windows nor Fedora is booting -- sorry, because I know it's a common typo, did you mean "if Windows is not booting"?

I'll see if I can actually disable the drives in BIOS. Should that work to hide the Windows drive or do I have to physically unplug it? (I can do that, I built this machine myself, I'm just wondering.)

Thanks, this is all really helpful!

[bob]

If Windows is not booting, then I'd just go ahead with the first option and overwrite the existing mbr. Grub Error 15 means that grub's lost part of itself and needs to make the connection between the two parts (mbr and distro).

Of course if you want to play around, you can try the second method by either unplugging or turning off the first drive. Heck, I've done it both ways with the same install - doing the 'usual' method to boot Fedora and Windows off the first drive, then for fun, I've unplugged the first drive and created a second mbr on the Fedora drive and reverse-booted Windows. The glitch with that is root's being identified as (hd1,0) ...second drive, first partition.... from the first install, then you're confusing it when Fedora now thinks "Am I (hd0) or (hd1)?" . Fun! And you learn a lot about grub and how to repair your computer after you've thrown it out the window.

[FortyArc]

I did the switcheroo procedure as you described, but Windows still won't boot. If the Fedora drive is first in BIOS, it just loads up Fedora, with no option for a second operating system. If the Windows drive is first, I get grub trying to load, and then error 15 again.

title Windows XP Professional
map (hd0) (hd1)
map (hd1) (hd0)
rootnoverify (hd1,0)
chainloader +1

Is this supposed to override what was on the Windows drive's mbr and replace it with something that works?

[FortyArc]

But -- I do have access to the files on the Windows side. Yay. That was the main thing I was worried about, actually. I'd like to get it bootable, but I was able to at least open it up from within Fedora. If I really have to I can salvage the data and reinstall Windows over there.

[bob]

In answer to your post #7, yes that's what should boot Windows. You know that Windows is on the 'first' drive, but when you disabled that drive, Fedora thinks it's on the first (and only) drive. That's why it's booting itself as (hd0,0) ....first partition of the first drive. So, then you've got to tell it to boot Windows, which by default is now called the second drive (hd1).

With the drive boot order switched and that entry put into Fedora's /boot/grub/grub.conf, you should be able to boot Windows from the grub menu. Again, it's pretty simple: Boot into Fedora, open a terminal, sign in as root (su -) and then use a text editor to add the entry to the bottom of the grub.conf . I probably would also put a comment (#) in front of "hiddenmenu" so that you'll see the new menu at boot. Then 'save', exit and reboot and test the Windows entry.

Of course, all this is assuming that Windows is booting off the first partition of that drive. If there's a hidden partition, such as a rescue partition for Windows, it may be booting at (hd1,1) instead of (hd1,0). If you do have problems, you can stop the boot, use the 'e' key and test a different partition. It will only affect that one boot attempt.

BTW, I've gotta get some sleep, so I'll wish you well and hope that someone else can jump in and lend a hand if you don't get it running right away.

[FortyArc]

I shouldn't have taken a break from this, now I need to go back and re-remember everything.

Okay, so: adding those lines to grub.conf didn't do any good. If I go into the BIOS and boot from one drive, I just get Fedora; if I boot from the other drive, I get error 15.

The line that starts with rootnoverify is the one telling it which partition to boot from, right? If I change that to hd(1,1) will that tell it to check a different partition instead of trying to boot hd(1,0)?

What happens if I take out the lines that start with map? I can't remember now whether the drives are plugged in in the 'switched' position or the right way around. The Fedora drive comes up first in the BIOS when I go to choose a boot drive, so I assume that means it's hd(0).

You said earlier: "by switching the bios boot, you still should be able to boot Windows independently no matter what". This isn't the case; Windows can't boot at all. If I try to boot from the 250GB hard drive (the one with Windows on it) I get error 15. Does this mean the damaged bootloader is indeed on that drive, somewhere? Is there a way I can look at its partitions from within Linux? If I open up Logical Volume Management I can see the drive in question under 'uninitialized entries' as /dev/sda with Partition 1 and Unpartitioned Space, and also /dev/sdb as a 20 GB drive with mount point /boot.

[bob]

Okay, thinking this out a bit more. I believe that you had overwritten Windows' mbr with Ubuntu's grub so it's currently not working since Ubuntu's gone and the half of grub that remains is searching in vain for it.

So, a solution may be to go to the Windows drive, which only contains Windows and (unplugging the other drives) restore the Windows bootloader. You can download a cd or floppy version of the Win98 startup and then use the 'fixmbr' instructions here: http://forums.fedoraforum.org/showthread.php?t=182740 or just check online - there are a ton of instructions about 'fixboot' and 'fixmbr' for Windows.

With Windows mbr restored, you should be able to bios-switch to at least boot each OS. The 'mapping' is still the way to instruct Fedora's grub to recognize another hard drive that wasn't present when it was set up. Once you've got Windows back in business, we can work on the ultimate solution.

[FortyArc]

Ok... guess I have to have a floppy drive after all. Man, and we thought those things were obsolete. That'll be my next try, then.

[bob]

As to mapping, here's some other links that might explain it better than I have:
http://wiki.archlinux.org/index.php/...Arch_Dual_Boot
http://blog.firetree.net/2005/08/26/...ows-with-grub/
http://www.linuxforums.org/forum/red...r-missing.html
http://www.linuxquestions.org/questi...e-sata-335189/

[BenTrein]

I've got a problem with a Windoze 7 and Fedora 11 dualboot.

History
I installed F11 with a WinXP dualboot. I then - a month or two later - downloaded and installed Windoze 7, which went fine. Then I used the instructions found elsewhere on this forum to "rescue an installed system" and rescue the old grub.

Problem
Now I get back to the grub menu on startup. F11 starts fine, but when I choose Windoze, the screen goes blank, and then comes back to the grub menu.

System

fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x02a302a3

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        5864    47102548+   7  HPFS/NTFS Windoze 7
/dev/sda2            5865        9561    29696000   83  Linux Fedora 11
/dev/sda3            9561        9727     1331200   83  Linux Swap

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x26cd3b61

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       19457   156288321   83  Linux Home

Grub

#boot=/dev/sda
default=0
timeout=10
splashimage=(hd0,1)/boot/grub/splash.xpm.gz
title Fedora (2.6.29.6-213.fc11.x86_64)
	root (hd0,1)
	kernel /boot/vmlinuz-2.6.29.6-213.fc11.x86_64 ro root=UUID=36cf5838-893c-445c-9b82-d97ef075d540 rhgb quiet
	initrd /boot/initrd-2.6.29.6-213.fc11.x86_64.img
title Fedora (2.6.29.5-191.fc11.x86_64)
	root (hd0,1)
	kernel /boot/vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=UUID=36cf5838-893c-445c-9b82-d97ef075d540 rhgb quiet
	initrd /boot/initrd-2.6.29.5-191.fc11.x86_64.img
title Fedora (2.6.29.4-167.fc11.x86_64)
	root (hd0,1)
	kernel /boot/vmlinuz-2.6.29.4-167.fc11.x86_64 ro root=UUID=36cf5838-893c-445c-9b82-d97ef075d540 rhgb quiet
	initrd /boot/initrd-2.6.29.4-167.fc11.x86_64.img
title Windoze
	rootnoverify (hd0,0)
	chainloader +1

I tried adding a few of the things above in the grub, but to no avail - the best I got was the message "Unknown device string, press any key to continue". Then I spent ten minutes looking for the "any" key :P and hit it; and it brought me back to the grub menu.

Please feel free to ask for any additional information, or please analyze what it wrong with this setup, and let me know. I can't find anyone on the web who's done it before me. Though I can hardly believe it.

[JEO]

Try chainloader +4 instead:

http://blog.lokonopa.com/grub-up-windows-7/