Ubuntu 8.10 installation – GRUB error 18

Over the Christmas break I’ve installed Ubuntu 8.10 on my main machine. The installation was not upgradeable without some serious wizardry (the /boot partition was too small, and increasing that on a full disk is not easy), so I decided to do a fresh install.

After going through all the installation steps, and booting up Ubuntu 8.10 for the first time, I was greeted with a GRUB error 18. Some Googling revealed that this was caused by the hard disk being too large for the BIOS to handle. And there was even a helpful post that described a three step process:

  • Set your hard disk for LBA mode
  • Install Ubuntu
  • Set your hard disk back to normal
Unfortunately, this didn’t work for me. The installation resulted in the same GRUB error. However, there is an easier fix.
GRUB error 18 means actually that the kernel cannot be found in the first 1023 cylinders. You can change that by creating a /boot partition that is completely within those first 1023 cylinders. So, after the first try at installing, and failing with the GRUB error, try this:
  • Restart your machine, with the Ubuntu CD as startup.
  • Install Ubuntu as normal, until you get to the partition information.
  • Select Manual from the partition options.
  • The only thing you need to change is the main partition (/). Delete the one that is on the disk now. The partitioner may tell you it needs to write changes to the disk – by all means, let it write them.
  • Next, create a partition at the very beginning of the hard disk, of sufficient size, but not too big (I decided on 1GB, but it may be better to go with 512KB or even smaller – not too small, since I couldn’t do an upgrade on my 128KB boot partition). Choose ext2 as file system – you won’t need journaling or anything fancy on that partition. Your mount point is /boot.
  • Finally, create the main partition, covering the remainder of the hard disk. Make the file system ext3 – you want the journaling etc. on this one.
  • You should now have a /boot partition at the beginning of your disk, a / partition for most of the rest, and a small swap partition (about twice the size of your memory). If not, you need to manually adjust the partitions until you have all three.
  • Continue with the rest of the installation.
Your mileage may vary, but this worked for me (it’s also the trick I used when installing 6.06LTS). Hope this helps someone!

10 Replies to “Ubuntu 8.10 installation – GRUB error 18”

  1. Thank you so much. I had the same frustration and your “cure” was the answer. The partition was definitely the problem. Manual did not seem to cooperate so went to the “guided” choice and made a semi accurate guess that worked out in the end.
    Anyway, thanks much. Jack

  2. hi Ronald,

    Can you explain how you did this step by step in a easy way? for a 160gig hard drive with xp my plan is to give Linux 50 gigs of that drive!!,
    the part that i don’t understand is the manually doing the partitions how would you do this is you want to give Linux about 50gigs of the drive, easy step by step would be nice.

    ps: having this issue for a 2 years now using windows xp and Ubuntu 7.10 every time i up grade to 8.4 or higher i get error 18 i get that error 18.. i use Acronis to back up partitions :-)) so i don’t loose anything

    that you have a nice day or night 🙂

    Sorry for the spelling
    thanks :-))))))

  3. Hmm, I’m not sure about upgrading 7.10 to 8.04 – my last upgrade turned into a full reinstall before I figured out I can run the Ubuntu Live version and use the partition manager there.

    The step-by-step instructions for the new install should give you some pointers. Unfortunately I can’t do any screen shots or something like that right now.

    Your best bet is to partition your drive before installing Ubuntu, so that you can select the partitions you set up earlier (or manually assign the partitions). The trick is to have a separate /boot partition, that is within the first 1023 cylinders of your hard drive. If you have XP on the drive, you may have to move that around to make some room at the beginning of the disk. Use the partition editor in the Live version to move and resize partitions relatively safely – I suggest making a backup before messing around with any of the partitions! 🙂

    Acronis is a good choice, and should give you no problems.

    Good luck and let me know how it works out!

  4. I will post my out come, thanks for the response..Ronald man i been with this situation for a long time now let see what happens 🙂

  5. hi Ronald,

    mi situation is that I have all ready create it and untitled partition about 50 gigs so how I go about making that partition of the first 1023 cylinders of the hard drive, i just don’t get that manually staff, sorry for the inconvenient. LOL

  6. I will post my out come, thanks for the response..Ronald man i been with this situation for a long time now let see what happens 🙂

  7. hi Ronald,

    mi situation is that I have all ready create it and untitled partition about 50 gigs so how I go about making that partition of the first 1023 cylinders of the hard drive, i just don’t get that manually staff, sorry for the inconvenient. LOL

  8. Well, here it is December 2011, and your solution is still helping people today. I followed your instructions and Ubuntu 8.10 booted right up. I can’t tell you how much I appreciate your sharing your knowledge.

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