I messed with my MBR

[keevvv]

Hey all,

I'm relatively new to Linux handling and here is what happened :

I have one HDD on my laptop which is partitionned to sda2 Windows (7) and sda3 Ubuntu. I installed Windows after Ubuntu, so I had to reinstall the GRUB, which is what I did. After this, the GRUB loader showed only Ubuntu and memtest as bootable, so being the newbie that I am, I tried reinstalling the MBR.

I did so with ms-sys package on sda, and now nothing will load as I have a message from Yukon PXE telling me there is no operating system to be found.

I have reinstalled GRUB on sda3, still nothing is recognized.

Now, here is the weird thing, there are three partitions, sda1 which I don't remember creating, is sized 1.6G and is the default boot (I cannot change on any partition the "bootable" tag under system-admin-disk utility).

Did I seriously mess something up with the MBR ? I'm thinking there is either some kind of special MBR for the laptop's hidden partitionned HDD or ms-sys did something wrong.

Any help is appreciated,

Thanks.

[drs305]

keevvv,

Welcome to Ubuntu and the Ubuntu forums! :-)

The extra partition could be a boot partition or a small recovery partition. Download and run the boot info script from the site linked below. Post the contents of the RESULTS.txt and we'll have a good idea how to put things back together again.

http://bootinfoscript.sourceforge.net (http://bootinfoscript.sourceforge.net)

It will help if you paste the contents between "code" tags, which you generate inside the post by clicking the # icon.

[oldfred]

Welcome to the forums.

We typically recommend lilo as it works like the windows boot loader over ms-sys as it is old. You could install the windows boot loader from the windows CD.

You may just have needed to run this to get grub's osprober to find windows:
sudo update-grub

Try reinstalling grub and booting into Ubuntu and run the update-grub.

New installs of windows 7 create a 100MB boot/recovery partition which has the first part of your boot and then the main install in the second partition. Vendors often add a recovery partition that is just an image of your drive to bring it back to like new & erasing everything.

If you want to know what is where from Ubuntu or liveCD:
Boot Info Script courtesy of forum member meierfra
Page with instructions and download:
http://bootinfoscript.sourceforge.net/
Paste results.txt, then highlight entire file and click on # in edit panel(code tags) to make it easier to read.
Or You can generate the tags first by pressing the # icon in the post's menu and then paste the contents between the generated [ code][ /code] tags.

[keevvv]

wow, wasn't expecting such a fast reply ! here is the code


Boot Info Script 0.55 dated February 15th, 2010

============================= Boot Info Summary: ==============================

=> Windows is installed in the MBR of /dev/sda

sda1: __________________________________________________ _______________________

File system:
Boot sector type: Unknown
Boot sector info:
Mounting failed:
mount: unknown filesystem type ''

sda2: __________________________________________________ _______________________

File system: ntfs
Boot sector type: Windows Vista/7
Boot sector info: No errors found in the Boot Parameter Block.
Operating System: Windows 7
Boot files/dirs: /Windows/System32/winload.exe

sda3: __________________________________________________ _______________________

File system: ext3
Boot sector type: Grub
Boot sector info: Grub 0.97 is installed in the boot sector of sda3 and
looks at sector 367873560 of the same hard drive for
the stage2 file. A stage2 file is at this location on
/dev/sda. Stage2 looks on partition #3 for
/boot/grub/menu.lst.
Operating System: Ubuntu 9.10
Boot files/dirs: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img

=========================== Drive/Partition Info: =============================

Drive: sda ___________________ __________________________________________________ ___

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition Boot Start End Size Id System

/dev/sda1 * 2,048 3,084,479 3,082,432 7 HPFS/NTFS
/dev/sda2 3,084,480 249,569,774 246,485,295 7 HPFS/NTFS
/dev/sda3 249,571,328 488,396,799 238,825,472 83 Linux


blkid -c /dev/null: __________________________________________________ __________

Device UUID TYPE LABEL

/dev/loop0 squashfs
/dev/sda2 58707C31707C17C8 ntfs
/dev/sda3 6aa0c236-9390-4b84-a918-c4c97c281231 ext3
/dev/sda: PTTYPE="dos"

============================ "mount | grep ^/dev output: ===========================

Device Mount_Point Type Options

aufs / aufs (rw)
/dev/sr0 /cdrom iso9660 (ro,noatime)
/dev/loop0 /rofs squashfs (ro,noatime)


=========================== sda3/boot/grub/grub.cfg: ===========================

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by /usr/sbin/grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s /boot/grub/grubenv ]; then
have_grubenv=true
load_env
fi
set default="0"
if [ ${prev_saved_entry} ]; then
saved_entry=${prev_saved_entry}
save_env saved_entry
prev_saved_entry=
save_env prev_saved_entry
fi
insmod ext2
set root=(hd0,3)
search --no-floppy --fs-uuid --set 6aa0c236-9390-4b84-a918-c4c97c281231
if loadfont /usr/share/grub/unicode.pf2 ; then
set gfxmode=640x480
insmod gfxterm
insmod vbe
if terminal_output gfxterm ; then true ; else
# For backward compatibility with versions of terminal.mod that don't
# understand terminal_output
terminal gfxterm
fi
fi
if [ ${recordfail} = 1 ]; then
set timeout=-1
else
set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/white
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
menuentry "Ubuntu, Linux 2.6.31-20-generic" {
recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
set quiet=1
insmod ext2
set root=(hd0,3)
search --no-floppy --fs-uuid --set 6aa0c236-9390-4b84-a918-c4c97c281231
linux /boot/vmlinuz-2.6.31-20-generic root=UUID=6aa0c236-9390-4b84-a918-c4c97c281231 ro quiet splash
initrd /boot/initrd.img-2.6.31-20-generic
}
menuentry "Ubuntu, Linux 2.6.31-20-generic (recovery mode)" {
recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
insmod ext2
set root=(hd0,3)
search --no-floppy --fs-uuid --set 6aa0c236-9390-4b84-a918-c4c97c281231
linux /boot/vmlinuz-2.6.31-20-generic root=UUID=6aa0c236-9390-4b84-a918-c4c97c281231 ro single
initrd /boot/initrd.img-2.6.31-20-generic
}
menuentry "Ubuntu, Linux 2.6.31-14-generic" {
recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
set quiet=1
insmod ext2
set root=(hd0,3)
search --no-floppy --fs-uuid --set 6aa0c236-9390-4b84-a918-c4c97c281231
linux /boot/vmlinuz-2.6.31-14-generic root=UUID=6aa0c236-9390-4b84-a918-c4c97c281231 ro quiet splash
initrd /boot/initrd.img-2.6.31-14-generic
}
menuentry "Ubuntu, Linux 2.6.31-14-generic (recovery mode)" {
recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
insmod ext2
set root=(hd0,3)
search --no-floppy --fs-uuid --set 6aa0c236-9390-4b84-a918-c4c97c281231
linux /boot/vmlinuz-2.6.31-14-generic root=UUID=6aa0c236-9390-4b84-a918-c4c97c281231 ro single
initrd /boot/initrd.img-2.6.31-14-generic
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
linux16 /boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
linux16 /boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
if [ ${timeout} != -1 ]; then
if keystatus; then
if keystatus --shift; then
set timeout=-1
else
set timeout=0
fi
else
if sleep --interruptible 3 ; then
set timeout=0
fi
fi
fi
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

=============================== sda3/etc/fstab: ===============================

# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc defaults 0 0
# / was on /dev/sda3 during installation
UUID=6aa0c236-9390-4b84-a918-c4c97c281231 / ext3 errors=remount-ro 0 1
/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0

=================== sda3: Location of files loaded by Grub: ===================


238.1GB: boot/grub/core.img
186.9GB: boot/grub/grub.cfg
188.3GB: boot/grub/stage2
238.1GB: boot/initrd.img-2.6.31-14-generic
130.6GB: boot/initrd.img-2.6.31-20-generic
238.1GB: boot/vmlinuz-2.6.31-14-generic
186.8GB: boot/vmlinuz-2.6.31-20-generic
130.6GB: initrd.img
238.1GB: initrd.img.old
186.8GB: vmlinuz
238.1GB: vmlinuz.old
=========================== Unknown MBRs/Boot Sectors/etc =======================

Unknown BootLoader on sda1

00000000 fa 31 c0 8e d8 8e d0 bc 00 7c 89 e6 06 57 52 8e |.1.......|...WR.|
00000010 c0 fb fc bf 00 06 b9 00 01 f3 a5 ea 20 06 00 00 |............ ...|
00000020 52 b4 41 bb aa 55 31 c9 30 f6 f9 cd 13 72 13 81 |R.A..U1.0....r..|
00000030 fb 55 aa 75 0d d1 e9 73 09 66 c7 06 8d 06 b4 42 |.U.u...s.f.....B|
00000040 eb 15 5a b4 08 cd 13 83 e1 3f 51 0f b6 c6 40 f7 |..Z......?Q...@.|
00000050 e1 52 50 66 31 c0 66 99 e8 66 00 e8 21 01 4d 69 |.RPf1.f..f..!.Mi|
00000060 73 73 69 6e 67 20 6f 70 65 72 61 74 69 6e 67 20 |ssing operating |
00000070 73 79 73 74 65 6d 2e 0d 0a 66 60 66 31 d2 bb 00 |system...f`f1...|
00000080 7c 66 52 66 50 06 53 6a 01 6a 10 89 e6 66 f7 36 ||fRfP.Sj.j...f.6|
00000090 f4 7b c0 e4 06 88 e1 88 c5 92 f6 36 f8 7b 88 c6 |.{.........6.{..|
000000a0 08 e1 41 b8 01 02 8a 16 fa 7b cd 13 83 c4 10 66 |..A......{.....f|
000000b0 61 c3 e8 c4 ff be be 7d bf be 07 b9 20 00 f3 a5 |a......}.... ...|
000000c0 c3 66 60 89 e5 bb be 07 b9 04 00 31 c0 53 51 f6 |.f`........1.SQ.|
000000d0 07 80 74 03 40 89 de 83 c3 10 e2 f3 48 74 5b 79 |..t.@.......Ht[y|
000000e0 39 59 5b 8a 47 04 3c 0f 74 06 24 7f 3c 05 75 22 |9Y[.G.<.t.$.<.u"|
000000f0 66 8b 47 08 66 8b 56 14 66 01 d0 66 21 d2 75 03 |f.G.f.V.f..f!.u.|
00000100 66 89 c2 e8 ac ff 72 03 e8 b6 ff 66 8b 46 1c e8 |f.....r....f.F..|
00000110 a0 ff 83 c3 10 e2 cc 66 61 c3 e8 62 00 4d 75 6c |.......fa..b.Mul|
00000120 74 69 70 6c 65 20 61 63 74 69 76 65 20 70 61 72 |tiple active par|
00000130 74 69 74 69 6f 6e 73 2e 0d 0a 66 8b 44 08 66 03 |titions...f.D.f.|
00000140 46 1c 66 89 44 08 e8 30 ff 72 13 81 3e fe 7d 55 |F.f.D..0.r..>.}U|
00000150 aa 0f 85 06 ff bc fa 7b 5a 5f 07 fa ff e4 e8 1e |.......{Z_......|
00000160 00 4f 70 65 72 61 74 69 6e 67 20 73 79 73 74 65 |.Operating syste|
00000170 6d 20 6c 6f 61 64 20 65 72 72 6f 72 2e 0d 0a 5e |m load error...^|
00000180 ac b4 0e 8a 3e 62 04 b3 07 cd 10 3c 0a 75 f1 cd |....>b.....<.u..|
00000190 18 f4 eb fd 20 72 65 61 64 20 65 72 72 6f 72 20 |.... read error |
000001a0 6f 63 63 75 72 72 65 64 00 0d 0a 42 4f 4f 54 4d |occurred...BOOTM|
000001b0 47 52 20 69 73 20 6d 69 73 73 69 6e 67 00 0d 0a |GR is missing...|
000001c0 42 4f 4f 54 4d 47 52 20 69 73 20 63 6f 6d 70 72 |BOOTMGR is compr|
000001d0 65 73 73 65 64 00 0d 0a 50 72 65 73 73 20 43 74 |essed...Press Ct|
000001e0 72 6c 2b 41 6c 74 2b 44 65 6c 20 74 6f 20 72 65 |rl+Alt+Del to re|
000001f0 73 74 61 72 74 0d 0a 00 8c a9 be d6 00 00 55 aa |start.........U.|
00000200

[oldfred]

It looks like something is wrong with sda1. You should try testdisk and see if it will fix it. It looks like sda1 must have been your boot partition as it has the boot flag and your install in sda2 is missing bootmgr and BCD. If windows will see sda1 you can try running chkdsk from a windows repairCD.

If testdisk does not repair sda1, you may be able to repair sda2 and add the missing bootmgr and BCD to that partition to make it bootable.

repairs including testdisk info & link to testdisk, testdisk is in repository and on most repairCDs
http://members.iinet.net.au/~herman546/p21.html
http://www.psychocats.net/ubuntucat/recoverdeletedfiles/
Instructions
http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step
http://www.cgsecurity.org/wiki/Menu_Analyse

If your PC did not come with a complete Vista or Win7 installation CD, you can download a Recovery Disc at the following links:
Windows Vista/7 Recovery Disc - for repairs only
http://neosmart.net/blog/2008/windows-vista-recovery-disc-download/
http://neosmart.net/blog/2009/windows-7-system-repair-discs/
Vista will not repair XP (they create the boot sectors differently) but can run chkdsk.
http://support.microsoft.com/kb/927392

How to fix Vista/Window 7 when the boot files are missing - rebuild BCD with bcdedit
http://ubuntuforums.org/showpost.php?p=5726832&postcount=4
Some advanced BCD rebuild, Vista:
http://ubuntuforums.org/showthread.php?t=1426103
http://support.microsoft.com/kb/927392

Grub's osprober does not find the windows install. It must be looking for BCD or bootmgr which are missing or not visible in the sda1 partition.

[drs305]

As oldfred has told you, getting Windows back is going to take some reconstruction.

You can get Ubuntu booting again a bit easier, and then work on restoring Windows as he describes. From a Karmic or later LiveCD Desktop, open a terminal and run the following.



sudo mkdir /mnt/temp
sudo mount /dev/sda3 /mnt/temp && sudo mount -B /dev /mnt/temp/dev && sudo mount -B /proc /mnt/temp/proc && sudo mount -B /sys /mnt/temp/sys && sudo mount -B /dev/pts /mnt/temp/dev/pts && sudo cp /etc/resolv.conf /mnt/temp/etc/resolv.conf && sudo chroot /mnt/temp
sudo apt-get update # Note: Checks Internet connection. If this command doesn't run, don't do the rest.
apt-get purge grub grub-pc grub-common
apt-get install grub-pc
update-grub

As you uninstall, you may get a warning about uninstalling the bootloader. Tab to OK.
As you are installing grub-pc, TAB to OK except for the partitioning screen. In that screen, make sure an asterisk is in the "sda" listing (if not, use the SPACE key to select it). Do NOT select any partitions, just the drive. Then TAB to OK to complete the installation.

The details of what you are doing are located in this post:
http://ubuntuforums.org/showthread.php?t=1581099

[keevvv]

Okay, so I've used testdisk to successfully rewrite a boot for sda1. If I restart without the LiveCD nothing happens, only an underscore flashing, which does not surprise me. However. If I try to reinstall grub here is what I get :


Creating config file /etc/default/grub with new version
grub-probe: error: cannot find a device for / (is /dev mounted?).
grub-probe: error: cannot find a device for /boot (is /dev mounted?).
grub-probe: error: cannot find a device for /boot/grub (is /dev mounted?).
/usr/sbin/grub-probe: error: cannot find a device for /boot/grub (is /dev mounted?).
No path or device is specified.
Try `/usr/sbin/grub-probe --help' for more information.
Auto-detection of a filesystem module failed.
Please specify the module with the option `--modules' explicitly.
note : For the instructions dsr gave I did not do all the mounting part beforehand and just used sudo at the start of each line as it was simpler and should work fine. I have restarted a few times to be sure I did not mount anything before, and it still did this.

[drs305]

Okay, so I've used testdisk to successfully rewrite a boot for sda1. If I restart without the LiveCD nothing happens, only an underscore flashing, which does not surprise me. However. If I try to reinstall grub here is what I get :

note : I did not do all the mounting part beforehand and just used sudo at the start of each line. I have restarted a few times to be sure I did not mount anything before, and it still did this.

You have to do the mounting; otherwise the commands will be run on the CD's files and not your real Ubuntu partition. The purpose of "chroot" is to allow the commands to act on the files in your actual install instead of failing when trying to write to the CD.

If you want to try to restore Windows before restoring Ubuntu, depending on whether or not your partition work with Windows is complete and successful, you can repair the Windows MBR with the following from the Ubuntu LiveCD:


sudo apt-get install lilo # Don't do the complete install as a bootloader. Disregard any messages.
sudo lilo -M /dev/sda mbr

That should restore the Windows MBR and allow you to boot directly into Windows if you prefer to do that first. Note this does not require the same type of mounting as for installing Grub.

[keevvv]

okay, it worked fine after reinstalling GRUB - the mount wasn't working at first, but that was because I was installing stuff before.

As a token of my gratitude, here is a picture :
http://oi55.tinypic.com/34q21yo.jpg