I messed up my MBR HELP!!!

[rockie12]

Hi I hope someone can help me. I have a toshiba notebook which was dual booting fine into Ubuntu 7.10 and windows XP. I have an external notebook usb harddrive caddy and wanted to install 8.10 on it. So I did and when it came time to tell it where to put the MBR, I did not click advanced... so it put it somewhere. Then when it was done, I removed the usb drive and my dualboot notebook gave me a grub error 21. Then it dawned on me that I did not tell it to put GRUB in the external drive and not mess with my internal drive, but now it is too late.

I tried the install again and told it to put the GRUB loader on the external drive, that did not work... then I did the install again and said to put it on the internal drive... and now I can only boot this box if I have the external drive and the usb flash drive that I installed ubuntu 8.10 from in their appropriate usb ports.

How can I fix the MBR on the internal drive to only show the windows and ubuntu 7.10 like I had before starting this mess?

Thanks in advance
Dean-O

[lovelyvik293]

To install the MBR again put the windows cd and go to the recovery consol and use the commands


fixmbr
fixboot

And then install the GRUB with live cd.

[lovelyvik293]

After installing the MBR your grub does not woks so you have to install the grub again.

[caljohnsmith]

If you don't have your Windows Install CD, you can restore a Windows MBR to your Windows drive from the Ubuntu Live CD. If you boot your Live CD, open a terminal (Applications > Accessories > Terminal) and run:

sudo lilo -M /dev/sda mbr
That will write a Windows equivalent MBR to your sda drive. After that, you should be able to boot straight into Windows again if you boot your Windows drive on start up. To boot Ubuntu you will have to change your BIOS to boot your external USB drive first. That should work assuming you have Grub properly installed to the MBR of the USB drive. Let us know how it goes or if you run into problems.

[rockie12]

Hi all

Thanks for the replies... my goal is to get my dual booting working again... not to just boot into windows. I had dual booting working on the notebook before I went to install 8.10 on an external usb drive... that is when things went south...

So if I want to get my notebook back to being able to dual boot windows and ubuntu 7.10... how do I do that? I do not want to boot the usb drive on this notebook.

If that was already stated and I missed it... I please restate it... I am a newbie here and love my dual boot world... I miss it terribly :)

Thanks
Dean-O

[caljohnsmith]

In order to get a clearer picture of your setup, how about downloading the attached "boot_info9.txt" file to your desktop, open a terminal (Applications > Accessories > Terminal) and do:

sudo sh ~/Desktop/boot_info9.txt
That will create a "BootInfo.txt" file on your desktop; please copy/paste the contents of that file to your next post. That will help clarify your setup in order to know what might be the best way to set up your dual boot.

[rockie12]

Hi I tried your boot_info9.txt file and I get the following error

80: arith: syntax error: "i+1"

[caljohnsmith]

That's strange, the script has never had a problem like that before. How about trying again with the newly attached "boot_info9_modified.txt" file:

sudo sh ~/Desktop/boot_info9_modified.txt

[rockie12]

That worked, but it created an empty file

[caljohnsmith]

OK, how about instead posting the output of:

sudo fdisk -lu
Also, for each of the drives fdisk lists, like sda, sdb, etc, please post the output of:

sudo xxd -l 2 -p /dev/sda
So replace "sda" above with each of your drives. Note "-l" is a lowercase L, not a one. And finally, for each command above that returns "eb48", please post:

sudo xxd -s 1049 -l 2 -p /dev/sda
And replace sda with the drives that previously returned "eb48". That will help clarify what your setup is like.

[rockie12]

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0xf932f932

Device Boot Start End Blocks Id System
/dev/sda1 * 63 103137299 51568618+ 7 HPFS/NTFS
/dev/sda2 103137300 153999089 25430895 83 Linux
/dev/sda3 153999090 156296384 1148647+ 5 Extended
/dev/sda5 153999153 156296384 1148616 82 Linux swap / Solaris

Disk /dev/sdb: 40.0 GB, 40007761920 bytes
255 heads, 63 sectors/track, 4864 cylinders, total 78140160 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x97509750

Device Boot Start End Blocks Id System
/dev/sdb1 63 74846834 37423386 83 Linux
/dev/sdb2 74846835 78140159 1646662+ 5 Extended
/dev/sdb5 74846898 78140159 1646631 82 Linux swap / Solaris

Disk /dev/sdc: 2038 MB, 2038431744 bytes
251 heads, 62 sectors/track, 255 cylinders, total 3981312 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0xc3072e18

Device Boot Start End Blocks Id System
/dev/sdc1 * 62 1478389 739164 6 FAT16
/dev/sdc2 1478390 3968309 1244960 83 Linux

[rockie12]

sudo xxd -l 2 -p /dev/sda
eb48

sudo xxd -l 2 -p /dev/sdb
33c0


sudo xxd -l 2 -p /dev/sdc
faeb

[rockie12]

sudo xxd -s 1049 -l 2 -p /dev/sda
0082

[caljohnsmith]

OK, first to restore your dual boot between Windows and 7.10, and also to install Grub to your 8.10 drive, try the following:

sudo grub
grub> root (hd0,1)
grub> setup (hd0)
grub> root (hd1,0)
grub> setup (hd1)
grub> quit
Please post the output of all the above commands, reboot, and you should get your old 7.10 Grub menu allowing you to boot Windows/7.10. Then if you can set your BIOS to boot your 8.10 drive, you should be able to boot 8.10. Let me know how it goes or if you run into problems.

[rockie12]

ok I entered those commands and they seemed to work... meaning I did not get any errors. So now I should be able to shutdown my notebook. Disconnect any external drives... cross my fingers and it should book like it id before with the windows/7.10?

Then if I shutdown and attach my external drive with 8.10 on it, start up the notebook go to the menu to choose which HDD to boot from, I should be able to boot from the external drive?

Just checking before I shutdown and disconnect stuff.

[caljohnsmith]

ok I entered those commands and they seemed to work... meaning I did not get any errors. So now I should be able to shutdown my notebook. Disconnect any external drives... cross my fingers and it should book like it id before with the windows/7.10?

Then if I shutdown and attach my external drive with 8.10 on it, start up the notebook go to the menu to choose which HDD to boot from, I should be able to boot from the external drive?

Just checking before I shutdown and disconnect stuff.
Yes to all your questions; let me know how it goes. :)

[rockie12]

:guitar:

Dude!!!! You Rock!!!! Take the rest of the day off with pay :)

Thanks Big time!!!

[meierfra.]

rockie12: I'm the person who wrote the script "boot_info9.sh". Since I have no idea why it did not work for you, could you help me debugging it?

Could you run both scripts again and then post the output of


ls -l /tmp
cat /tmp/BootFiles0/Error_Log
cat /tmp/BootFiles/Error_Log

Thanks

[caljohnsmith]

:guitar:

Dude!!!! You Rock!!!! Take the rest of the day off with pay :)

Thanks Big time!!!
Glad to hear that did the trick; if you have a little time, it would be great if you could help out both meierfra and me by posting the info that meierfra asked for, because we both would like to know why the script failed to run on your setup. If you don't have time though, that's fine. :)

[rockie12]

Sure thing... how do I do that? Where is the URL to do that?

Dean-O

[caljohnsmith]

Thanks for helping us out, how about first trying meierfra's latest script by doing:

cd ~/Desktop && wget 'http://home.comcast.net/~ubuntu_grub/boot_info_script.txt' && sudo sh ./boot_info_script.txt
And post the contents of the boot_info_results.txt file on your desktop if the script above works. If you get an error again, please let us know what it is and also post:

ls -l /tmp /tmp/Boot*
cat /tmp/Boot*/Error_Log
And I'm sure meierfra will be around soon to ask for any additional info he needs for troubleshooting the script.

[rockie12]

The second script that was attached to the thread was able to run and allowed me to create the files. I then pasted the contents of those files into this thread... then I was instructed to do the steps listed above to set up grub on hd0 and hd1

That is what fixed it.

[meierfra.]

rockie 12, I figured out why the script was not working for you. The command "sh" behaves differently in Ubuntu 8.10 than in some of the earlier versions of Ubuntu. To succesfully run the scripts you downloaded one has to use "bash" instead of "sh.

Thanks for you input.

[rockie12]

I was able to run the second script with sh just fine... no error on the math line 80 where it had x + 1 line