HOWTO: Boot & Install Ubuntu from the Grub Rescue Prompt

[drs305]

c.cobb,

If I remove the isoscan kernel option in the Lucid 10.04 LTS 3 I get a 'Can't open /dev/sr0: No medium found' error message and the system won't boot to the LiveCD Desktop. Here is the menuentry I am using:

menuentry 'ISO Lucid.1 64 ' {
isofile=ubuntu-10.04.3-desktop-amd64.iso
loopback loop (hd1,6)/iso/$isofile
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/iso/$isofile noprompt noeject
initrd (loop)/casper/initrd.lz
}

[xanderman]

I am stuck on Step 6 - Load the Linux kernel and initrd image.

The following code:
linux /casper/vmlinuz boot=casper iso-scan/filename=/<ISO-name.iso> noprompt noeject

produces this error:
error: cannot read the Linux header.

PLEASE HELP ME!

[drs305]

xanderman,

Welcome to the Ubuntu forums.

The reference to /casper seems to indicate you are not using a standard installation. 'casper' usually involves trying to boot from an ISO image and not from a installed Ubuntu release.

I would suggest booting a LiveCD and installing the Boot Repair app. It may be able to fix your problem, and if not it will provide an option to run the 'boot info' script, which will provide us with information needed to help you.

You can learn more about the Boot Repair app from its link in my signature line.

[mufler]

Hey guys,

I got into "grub rescue" after trying to reinstall grub2. (I did the reinstall because of dual boot issue when i recently installed window7, in addition to ubuntu 10.04 LTS which was already installed on the netbook)

The error message i get is "error: incompatible licence". And then i am left in the rescue mode. I tried to boot fra a usb stick with ubuntu Live, and guess what. I get prompted with username and password. This has never happend before. Last time I used this LIVE ISO was 2 days ago. The problem is that i just cannot get logged in the LIVE ubuntu. Tried the ubuntu username with blank password. Did ctrl+shift+f1, set password for a user and then alt+f7, but still no go. So here i am stuck.

I have also tried to work inside rescue mode with your advices. I can get into ls (hd0,1)/boot/grub and the .mods are there, but when i type insmod (name of the mod) I get incompatible licence error message. I feel pretty stucked at this stage. I can't execute essential commands in rescue mode, and live iso wont let me in either.

Any suggestions?

[drs305]

mufler,

Welcome to the Ubuntu Forums. I'm out on a business trip and am not logging into the site frequently this week so I'm sorry your post didn't receive a more prompt response.

Normally the 'incompatible license' message means that the core.img that was created when 'grub-install' was created used different modules. Perhaps you were using a newer CD than the one with which you installed Grub originally.

What I would recommend is to boot a LiveCD and purge and reinstall Grub 2. To do this, you have to boot the CD then 'chroot' into your Ubuntu installation. The 'chroot' allows the commands you run on the LiveCD take their action on your real installation.

I don't know how much experience you have, but the instructions on how to do this are in the 'Chroot' link in my signature line. If you have questions, just ask.

[pirog]

Hi guys, drs305!

One of them days I turned off my IBM T23 with a push of a power button because it had froze. Upon restarting it, I was greeted with a blinking cursor and the following message:

error: hd0 read error
grub rescue>_

“ls” gives “(hd0), (hd0,msdos5), (hd0,msdos1) (fd0)”

My guess is that the partition table is intact, hard drive is not dead, grub2 can't see the first block and hence can't boot. I finally logged into LiveCD account (took about 40 minutes with the specs) and tried to mount the drives to save the data. Nautilus didn't show any. Then I remembered (!) that the “/home” partition was encrypted at the install time. BTW it is Mint Katya (11).

Anyways, when in “grub rescue” mode I can't load any modules, heck, I can't list any folders with “

ls (hd0,msdos1)/

” (giving me the “error: hd0 read error”) presumably because of encrypted disks. Which btw can't be mounted in the Live-environment.

I am thinking of using LiveCD to re-install grub2 or try to mount encrypted drives through the magic of … hell, I am not too sure how to mount encrypted drives in live-environment. I searched but to no avail. I am not even sure what encryption type is on the HD.

Do you guys have any ideas on the "pickle" of an issue?

Thanks,

p.

[drs305]

Hi guys, drs305!

One of them days I turned off my IBM T23 with a push of a power button because it had froze. Upon restarting it, I was greeted with a blinking cursor and the following message:

error: hd0 read error
grub rescue>_

“ls” gives “(hd0), (hd0,msdos5), (hd0,msdos1) (fd0)”

My guess is that the partition table is intact, hard drive is not dead, grub2 can't see the first block and hence can't boot. I finally logged into LiveCD account (took about 40 minutes with the specs) and tried to mount the drives to save the data. Nautilus didn't show any. Then I remembered (!) that the “/home” partition was encrypted at the install time. BTW it is Mint Katya (11).

Anyways, when in “grub rescue” mode I can't load any modules, heck, I can't list any folders with “

ls (hd0,msdos1)/

” (giving me the “error: hd0 read error”) presumably because of encrypted disks. Which btw can't be mounted in the Live-environment.

I am thinking of using LiveCD to re-install grub2 or try to mount encrypted drives through the magic of … hell, I am not too sure how to mount encrypted drives in live-environment. I searched but to no avail. I am not even sure what encryption type is on the HD.

Do you guys have any ideas on the "pickle" of an issue?

Thanks,

p.

Hey pirog,

I'm going to be pretty scarce on the forums for the next month and a half. I don't have a ready answer for you as I'm not educated on all the aspects of encrypted drives. Some of the things I'd recommend wouldn't work because of the encryption.

What I'd recommend for now is to start your own thread and describe your situation. There are a lot of bright people on this forum and some understand and use encryption. Mention that the partition is encrypted in the thread title so you get the attention of users who can help you. The good news is that your /home partition doesn't come into play during the initial part of the boot process so you might be able to fix things even with the encrypted home partition.

I'd suggest running the boot info script. The script generates a file called RESULTS.txt which provides a lot of information about the status of your boot files. It can be run from a LiveCD, as can the tool mentioned next.

You can try to fix things with the Boot Repair tool. If it can't help, it would at least provide the option to run the boot info script for you. You can learn more about Boot Repair from the link in my signature line. (Also BIS)

Best of luck. If I'm on the forums I'll check for your new thread and offer any help I can.

[pirog]

Hey pirog,

I'm going to be pretty scarce on the forums for the next month and a half. I don't have a ready answer for you as I'm not educated on all the aspects of encrypted drives. Some of the things I'd recommend wouldn't work because of the encryption.

What I'd recommend for now is to start your own thread and describe your situation. There are a lot of bright people on this forum and some understand and use encryption. Mention that the partition is encrypted in the thread title so you get the attention of users who can help you. The good news is that your /home partition doesn't come into play during the initial part of the boot process so you might be able to fix things even with the encrypted home partition.

I'd suggest running the boot info script. The script generates a file called RESULTS.txt which provides a lot of information about the status of your boot files. It can be run from a LiveCD, as can the tool mentioned next.

You can try to fix things with the Boot Repair tool. If it can't help, it would at least provide the option to run the boot info script for you. You can learn more about Boot Repair from the link in my signature line. (Also BIS)

Best of luck. If I'm on the forums I'll check for your new thread and offer any help I can.

Hi drs305,

Thanks for the tips. You are certainly right in that I start a new thread, but I thought it would be a good place to start my search. I was hoping you had had a similar problem, since yours is related to mine.

I'll give the script a try and if anything good comes of it, I'll let you know. The thing about “/home” partition, you are right it won't come into play until later. I still think it is the grub2 issue. If I ever get to solve this problem, I'll write it up in a new post for others to see.

Thanks for your suggestions mate.

Regards,

p.

[HotForLinux]

How can I work with grub2's command line inside Ubuntu?

• If you don't find the modules, try the alternate location:  ls (hdX,Y)/usr/lib/grub/i386-pc

In my case one location has 204 modules and the other 207 with only 9 differences is that normal? I thought that duplicate info was a sin.

It suddenly reminded me the disorder in *******'s directories.

[drs305]

How can I work with grub2's command line inside Ubuntu?

• If you don't find the modules, try the alternate location:  ls (hdX,Y)/usr/lib/grub/i386-pc

In my case one location has 204 modules and the other 207 with only 9 differences is that normal? I thought that duplicate info was a sin.

It suddenly reminded me the disorder in *******'s directories.

I've never closely inspected/compared the two folders, but I know that the grub folder used for booting contains at least a couple of files that are generated 'locally' - grub.cfg (the menu) and grubenv. I'm sure there are several others as well, which would explain the differences.