HOWTO: Restore GRUB (if your MBR is messed up)

[RonKZ]

avoid? hell, for a newbie prior to actually being booted into whatever distro, commandline is virtually impossible, it's plain wilderness stuff.

[perspectoff]

avoid? hell, for a newbie prior to actually being booted into whatever distro, commandline is virtually impossible, it's plain wilderness stuff.

These are cut and paste instructions, mate. Perhaps you should join Hare Krishna. They'll take care of you if you've had too many drugs to cut and paste.

[xristos]

I may be missing your point though, if so, please forgive me

This way the user must know the correct hd(0,6) .
So I believe that this way is actually more complex

[jars_u]

Ok, sort of figured out my problem. The offender was a 2nd PATA drive I had salvaged from an old computer and installed in my machine. When I removed that and did a clean install of Kubuntu on the partition I had made previous on my SATA drive - the defaults for GRUB worked fine. I can now get back into Windows (who ever thought I would be so happy to the see the Windows welcome screen...) and can also boot to Kubuntu.

Going to try and few other things and see if I can't get that old PATA working and remort it for FAT32 - should be able to use it to share files between Win/Linux right?

Now for the easy question - how do I extend the default time that GRUB gives you to make a selection?

[ghostintheshell]

[...]

Now for the easy question - how do I extend the default time that GRUB gives you to make a selection?

sudo cp /boot/grub/menu.lst /boot/grub/menu.lst.bkp
sudo gedit /boot/grub/menu.lst

and modify here:

## timeout sec
# Set a timeout, in SEC seconds, before automatically booting the default entry
# (normally the first entry defined).
timeout        1

timeout X ==> X sec.

[commodore]

I have two grubs accidently. They are on different partitions. Someone sayd I should reinstall grub. I tried to install it on where it was first, but I get this: xfs_freeze: specified file ["/boot/grub"] is not on an XFS filesystem

[syklitengutt]

have some difficulties with the two first suggestions.
When booting up my pc, I directly jump into windows.

I tried installing grub from cd and when its finished it jumps straight back to
selecting partitions. Dont know why.
So I then tried to install via live cd.
type su and try the password I have on my linux partition, and it doesnt work.
I also tried every other possible passw. but still it doesnt work.

fdisk:
ubuntu@ubuntu:~$ sudo fdisk -l

Disk /dev/hda: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 3696 29688088+ 7 HPFS/NTFS
/dev/hda2 3697 14593 87530152+ 5 Extended
/dev/hda5 3697 6307 20972822+ 83 Linux
/dev/hda6 6308 6361 433723+ 82 Linux swap / Solaris
/dev/hda7 6362 14593 66123508+ 7 HPFS/NTFS

where hda1 is parition C: on windows
hda2 is unknown, but I think its where hda5 and hda7 is written to.
hda 5 is my linux (used to be hda6 and hda7 is D: in windows (used to be hda5

so I really need help guys....

[armada]

Isn't it easier to do this:

1. Pop in the Live CD, boot from it until you reach the desktop.
2. Open a terminal window or switch to a tty.
3. Type "grub"
4. Type "root (hd0,6)", or whatever your harddisk + boot partition numbers are (my /boot is at /dev/sda7, which translates to hd0,6 for grub).
5. Type "setup (hd0)", ot whatever your harddisk nr is.
6. Quit grub by typing "quit".
7. Reboot.

This did work wonder in restoring the MBR of my Compaq Armada 1750 after I restored the laptop from Ghost. Yet the laptop's special partitition, where the BIOS tools are located, is no longer accessible through pressing F10 duing POST.

I can live with this as I still can access the BIOS settings through using a floppy. Yet I wonder if there is a way to have both Grub and the easy F10 access to the BIOS tools.

I suspect that the original Compaq MBR is Windows-compatible. I may be able to Windows' boot.ini to access the Linux partitions and still keep the original BIOS access intact.

Thanks.

[StormWatcher]

Isn't it easier to do this:

1. Pop in the Live CD, boot from it until you reach the desktop.
2. Open a terminal window or switch to a tty.
3. Type "grub"
4. Type "root (hd0,6)", or whatever your harddisk + boot partition numbers are (my /boot is at /dev/sda7, which translates to hd0,6 for grub).
5. Type "setup (hd0)", ot whatever your harddisk nr is.
6. Quit grub by typing "quit".
7. Reboot.

I may be missing your point though, if so, please forgive me

This method did bring back my grub, however I get an error when I boot.
My partition list is:
/dev/hda1 Windows NTFS (Has my XP Pro on it)
/dev/hda2 Extended 3 (Has my Ubuntu on it, and I can mount and look at all my data)
/dev/hda5 Swap
/dev/hda4 Unformatted

I opened a terminal window and did the following:

grub> root (hd0,1)
 Filesystem type is ext2fs, partition type 0x83

grub> setup (hd0)
 Checking if "/boot/grub/stage1" exists... yes
 Checking if "/boot/grub/stage2" exists... yes
 Checking if "/boot/grub/e2fs_stage_5" exisits... yes
 Running "embed /boot/grub/e2fs_stage1_5 (hd0)"... 16 sectors are embedded. succeeded
 Running "install /boot/grub/stage1 (hd0) (hd0)1+16 p (hd0,1)/boot/grub/stage2 /boot/grub/menu.list"... succeeded
Done.

The first time I ran this command I did get errors, but it said they were not fatal. I do not know what they where, but now it seems to succeed just fine.


But when I boot my screen looks like:

  Booting 'Ubuntu. kernel 2.6.12-10-386 '

root (hd0,2)
 Filesystem type unknow, partition type 0x5
kernel /boot/vmlinuz-2.6.12-10-386 root=dev/hda3 ro quiet splash

Error 17: Connot mount selected partition

Press any key to continue...

Also when I boot using the the rescue option and then type:

sh-3.00# grub-install /dev/hda2

I get:

The file /boot/grub/stage1 is not read correctly.

So now I am not sure what I should do.... My linux is on hda2. I have very little knowledge of linux. The menu still boot my Windows XP. I wish it was there other way around.

Thanks for your help.

[StormWatcher]

If anyone caree, I was able to fix my problem by editing the menu.lst file in /boot/grub. I changed the file to read:

root (hd0,2)
kernel /boot/vmlinuz-2.6.12-10-386 root=dev/hda3 ro quiet splash

to

root (hd0,1)
kernel /boot/vmlinuz-2.6.12-10-386 root=dev/hda2 ro quiet splash

and all works fine now. This thread helped alot. Thanks.