Grub issues with 10.04

[phil1349]

I have just installed Kubuntu 10.04 on my system and first impressions are good, I like it. The only problem is with grub. I also have Mandriva installed on my hard disk and grub seems to have found it but if I try and start it, I get the following error message:

VFS: Cannot open root device "UUID=302f2a4e-36f3-422d-89b8-8954aef6dfdc" or unknown - block (0,0)
Please append or correct "root=" boot option; here are the available partitions:
Kernel panic - not syncing :VFS: unable to mount root fs if unknown-block (0,0)

With Kubuntu 8.10, the predecessor to 10.04 the menu.lst entry was:

# This entry automatically added by the Debian installer for an existing
# linux installation on /dev/sda2.
title linux (on /dev/sda2)
root (hd0,1)
kernel /boot/vmlinuz BOOT_IMAGE=linux root=UUID=302f2a4e-36f3-422d-89b8-8954aef6dfdc splash=silent vga=788
initrd (hd0,1)/boot/initrd.img
savedefault
boot

This worked fine but with 10.04, the grub.cfg entry is:

}
menuentry "linux (on /dev/sda2)" {
insmod ext2
set root='(hd0,2)'
search --no-floppy --fs-uuid --set 302f2a4e-36f3-422d-89b8-8954aef6dfdc
linux /boot/vmlinuz BOOT_IMAGE=linux root=UUID=302f2a4e-36f3-422d-89b8-8954aef6dfdc splash=silent vga=788
initrd (hd0,1)/boot/initrd.img

This produces the error message above. Note the change from (hd0,1) in 8.1 to (hd0,2) for 10.04 but initrd still points to (hd0,1). Also insmod ext2 when the mandriva installation uses ext3 as a file system.

I have tried altering the appropriate parameters in grub.cfg but it does not make any difference.

I also have Windoze on the hd and it starts this no problem.

Anyone else had this problem & any ideas on a fix ?

[dibl]

Re: Grub issues with 10.04

If you are accustomed to working with legacy Grub, then you need to know that you're going to have a little learning experience with Grub 2: http://kubuntuforums.net/forums/inde...opic=3106368.0

Hints:

- Grub 2 counts partitions (but not devices) differently, beginning with "1"

- You don't edit /boot/grub/grub.cfg directly -- you edit the /etc/default/grub and the files in /etc/grub.d/ , and then run "sudo update-grub" to regenerate /boot/grub/grub.cfg.

[oshunluvr]

Re: Grub issues with 10.04

Did you manually put that entry in or did update-grub do it?

Just as a test - edit /boot/grub/grub.cfg and change

initrd (hd0,1)/boot/initrd.img

to

initrd /boot/initrd.img

If it works - and running update-grub causes it to change back to the previious entry, you'll have to put the correct entry into 40_custom

[Snowhog]

Re: Grub issues with 10.04

If you are accustomed to working with legacy Grub, then you need to know that you're going to have a little learning experience with Grub

It is done! dibl, with this reply, has reached 10,000 posts on KFN.!!

[oshunluvr]

Re: Grub issues with 10.04

Hey - you're only 183 away... whats that two more days

[Snowhog]

Re: Grub issues with 10.04

Maybe sometime this weekend. It isn't easy keeping up with the dibl!!

[phil1349]

Re: Grub issues with 10.04

Thanks to Dibl for the advice.

It looks like more than a little learning experience with Grub2 but I shall give it a go. It looks like it is the initrd parameters which are wrong so I will try this first.

It does pose the question why did Grub 2 get this wrong? My experience of legacy Grub is that it always got things right & I never had a problem with it.

[oshunluvr]

Re: Grub issues with 10.04

Wow - you didn't have a lot of time using grub legacy did you!!!
(I'm not trying to insult you - just kidding around)
I used lilo for years before I finally grudgingly gave into grub.

It seems like the developers of just about any project release about two or three months ahead of when they should. Of course - I can't really complain much. It's not like they're getting paid. 8)


Back to the topic:

I noticed when I did an install of a distro that was grub-legacy based (I let it install grub-legacy to the partition rather than the master boot record), grub-pc created the entry for it incorrectly. The root=(hd0,1) and initrd (hd0,1) lines were both wrong. That's why I suggested the edit above.

[dibl]

Re: Grub issues with 10.04

It isn't easy keeping up with the dibl!!

The dibl definitely needs to find better uses for his time! :P

[Snowhog]

Re: Grub issues with 10.04

What, you don't know that "the time spent with Linux is not deducted from ones lifespan."?

[phil1349]

Re: Grub issues with 10.04

I am just curious as how Grub 2 got root=(hd0,2) correct in grub.cfg but initrd=(hd0,1) which is wrong. I manually edited grub.cfg (yes, I know you're not supposed to do it this way) to initrd=(hd0,2) and surprise, everything worked.

I need to work out how to edit the script files as of course everytime grub is updated, grub.cfg gets changed back to the incorrect value.

[oshunluvr]

Re: Grub issues with 10.04

I too am curious because this is exactly how it happened on my machine.

I haven't dug deep enough in to figure out what's wrong with os_prober, but something is amiss.

One way to handle this for you is to copy the corrected stanza(s) into 40_custom and then make 30_os_prober not executable.

[phil1349]

Re: Grub issues with 10.04

That sounds like a good idea from oshunluvr, I shall give it a try. I also intend to have a play with ubuntu 10.04 to see if it has the same problem. If not, it may be easier to diagnose the problem with os_prober.

[GreyGeek]

Re: Grub issues with 10.04

If you are accustomed to working with legacy Grub, then you need to know that you're going to have a little learning experience with Grub

It is done! dibl, with this reply, has reached 10,000 posts on KFN.!!

RATS! I missed this event! >

I only noticed when he hit 1008.

So, Dibl, what is your favorite local eating place? Send me the address and I'll see to it that you have a nice free meal waiting for you at your convenience!

[dibl]

Re: Grub issues with 10.04

So, Dibl, what is your favorite local eating place? Send me the address and I'll see to it that you have a nice free meal waiting for you at your convenience!

Hey Thanks GG!

Well, if you're ever in Dayton, Ohio, I'll be delighted to take you there in person and you can buy the beer.

Actually I'm headed out of town tomorrow on a road trip, so don't come until next week!