Grub "Invalid Signature" error when booting windows

[SuaSwe]

hd0,0 (equal to /dev/sda1) would be the first partition on the first hard drive, which I believe is the one GRUB2 should be pointing at as that's the system partition, according to what you've described (makes sense size-wise as well). As such, I personally cannot see any issues with your grub.cfg file and its reference to the Windows drive; it would appear that the problem lies elsewhere.

Did anything at all change before all this happened, especially hardware changes? Could you find out what the exact error was that you got when you were still using GRUB Legacy? GRUB2 isn't exactly a well-known entity as it stands.

[cak3]

So, I didn't to have to restore the windows MBR again, so I decided to install grub to the one drive that didn't have a bootloader yet (/dev/sdb). I went to boot windows from that, and I got a different error! "BOOTMGR not found..." It told me to press Ctrl+alt+del to restart, which suggested that it was a windows problem, since grub seems to just take you back to the menu if it can't boot. Anyway, I didn't want to deal with a new problem, so I said, heck with it, and installed grub to the first HDD (with windows on it). And it worked.

Which is great, but weird, since I am pretty sure I was able to boot when grub was installed on a different drive...

I am not complaining, since it works. I might mess around some more later, to figure out more about how this works, but for now I am done. Thanks for the help.

[zulek87]

hi!

I got same issue.

After installing ubuntu 9.10 beta grub2 couldn't find my Win Xp.
So i followed the rules:

# apt-get install os-prober
# update-grub2

And it worked fine, till I updated my grub2 to the grub-pc.

Now I have exactly the same message: Invalid signature


I have grub installed at windows partition

/////////////////////////////////////////////////////////////////////

So i solved it.

my disk with windows and linux is /dev/sdb

sudo gedit /boot/grub/device.map

(hd0) /dev/sda change to (hd0) /dev/sdb

save

then

sudo os-prober
sudo update-grub
sudo reboot

[DrWarm]

Sorry could you explain how you installed grub on the windows partition (if that's what you did)?

When I update grub2 i get:

sudo update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-2.6.31-14-generic
Found initrd image: /boot/initrd.img-2.6.31-14-generic
Found memtest86+ image: /boot/memtest86+.bin
Found Windows 7 (loader) on /dev/sdb1
grub-probe: error: Cannot find a GRUB drive for /dev/sdb1.  Check your device.map.

done

Now that line of grub-probe with the error makes me think it's that, so i checked out /boot/grub/device.map but got only:

(hd0)	/dev/sda

So all i need to do is:

(hd0) /dev/sda change to (hd0) /dev/sdb

I don't want to try it until I've had confirmation from someone, as I'm not super keen to reinstall windows again, as i just did it!

Anyway this is my output from fdisk:

sudo fdisk -l /dev/sda

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x8d2c0565

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2549    20474811    5  Extended
/dev/sda2            2550      121601   956278784    7  HPFS/NTFS
/dev/sda5               1         486     3903732   82  Linux swap / Solaris
/dev/sda6             487        1459     7815591   83  Linux
/dev/sda7            1460        2549     8755393+  83  Linux

sudo fdisk -l /dev/sdb

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0001f164

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1          13      102400    7  HPFS/NTFS
Partition 1 does not end on cylinder boundary.
/dev/sdb2              13        5737    45977600    7  HPFS/NTFS
/dev/sdb3           11430      121601   884956160    7  HPFS/NTFS

So obviously windows is located on hd2, and i think that 100mb boot partition it makes is sdb1.

I want to be careful with this, as I only just reinstalled windows 7 again, and don't want to mess it up! Any help would be great.

Thanks

[satellite360]

Removed - see response below

[satellite360]

Sorry could you explain how you installed grub on the windows partition (if that's what you did)?

When I update grub2 i get:

sudo update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-2.6.31-14-generic
Found initrd image: /boot/initrd.img-2.6.31-14-generic
Found memtest86+ image: /boot/memtest86+.bin
Found Windows 7 (loader) on /dev/sdb1
grub-probe: error: Cannot find a GRUB drive for /dev/sdb1.  Check your device.map.

done

Now that line of grub-probe with the error makes me think it's that, so i checked out /boot/grub/device.map but got only:

(hd0)	/dev/sda

So all i need to do is:


I don't want to try it until I've had confirmation from someone, as I'm not super keen to reinstall windows again, as i just did it!

Anyway this is my output from fdisk:

sudo fdisk -l /dev/sda

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x8d2c0565

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2549    20474811    5  Extended
/dev/sda2            2550      121601   956278784    7  HPFS/NTFS
/dev/sda5               1         486     3903732   82  Linux swap / Solaris
/dev/sda6             487        1459     7815591   83  Linux
/dev/sda7            1460        2549     8755393+  83  Linux

sudo fdisk -l /dev/sdb

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0001f164

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1          13      102400    7  HPFS/NTFS
Partition 1 does not end on cylinder boundary.
/dev/sdb2              13        5737    45977600    7  HPFS/NTFS
/dev/sdb3           11430      121601   884956160    7  HPFS/NTFS

So obviously windows is located on hd2, and i think that 100mb boot partition it makes is sdb1.

I want to be careful with this, as I only just reinstalled windows 7 again, and don't want to mess it up! Any help would be great.

Thanks

DrWarm, try adding this to /etc/grub.d/40_custom

menuentry "Windows 7 (on /dev/sdb1)" {
insmod ntfs
set root=(hd1,1)
chainloader +1
}

Not a fix, exactly, but should allow you to access your Windows partition until the os-prober starts working properly

[DrWarm]

Wow thanks alot, worked a treat!!!!! Thanks again!

[elgordo123]

I had this same problem after and update to Ubuntu 9.10. Took forever to find solution - nothing on this thread worked, but lead me in right direction.
Noticed when I did sudo update-grub it came back with weird errors so did this:
sudo apt-get install os-prober
sudo os-prober, made sure it showed both linux and windows
sudo mv /boot/grub/device.map /boot/grub/device.map.bak
sudo update-grub (came back clean)
reboot (all is well)

[jtliii]

Thanks elgordo123! That fixed it for me.

[easy2002]

sudo apt-get install os-prober
sudo os-prober, made sure it showed both linux and windows
sudo mv /boot/grub/device.map /boot/grub/device.map.bak
sudo update-grub

thank you very much!