1

I am booting ubuntu 12.04 from a usb made with linux live usb creator. It is fine as long as I select the nomodeset option at the purple ubuntu screen.

The question is:

How can I set this mode to be the default one so I don't have to do it every time?

If I add the option to /etc/default/grub it doesn't do anything and if I

sudo update-grub 

I get this error

"/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?)."

how to fix this ?

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  • Have you chroot before running update-grub?
    – Maythux
    Dec 21, 2013 at 12:55
  • No. I am new to this can you explain a bit better. What does chroot do?
    – Redridge
    Dec 21, 2013 at 13:13
  • Ok write down all steps you have done... how you add nomodeset
    – Maythux
    Dec 21, 2013 at 13:17
  • I go to /etc/default/grub and i find the line with the options. I add after "quiet splash" "nomodeset". That's all I did actually.
    – Redridge
    Dec 21, 2013 at 13:21
  • you want to update grub in your live usb or that on your harddisk?
    – Maythux
    Dec 21, 2013 at 13:28

1 Answer 1

0

Boot your machine with Ubuntu Live CD and select Trying Ubuntu without installation option when it is prompted (Live CD mode)

Identify the root partition By terminal

sudo fdisk -l

This command will shows all disks connected. The entry having a * near the device name will be the root partition.(urs is sdb1)

Mount the root partition

Create a mounting point

mkdir  /mnt

Now mount your root partition

Sudo mount /dev/sdb1  /mnt   

Run the following commands to export the pesudo file system of Live CD to your would be root file system soon.

$ sudo mkdir /mnt/dev
$ sudo mkdir /mnt/proc
$ sudo mkdir /mnt/sys
$ sudo mount ‐‐bind /dev /mnt/dev
$ sudo mount ‐‐bind /proc /mnt/proc
$ sudo mount ‐‐bind /sys /mnt/sys

Change the root file system of live system to your hard disk

$ sudo chroot /mnt

update GRUB

$ sudo upate-grub 

Reboot and eject Ubuntu Live CD

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  • when I use sudo mount /dev/sdb1 / /mnt I get the following output
    – Redridge
    Dec 21, 2013 at 15:30
  • Usage: mount -V : print version mount -h : print this help mount : list mounted filesystems mount -l : idem, including volume labels
    – Redridge
    Dec 21, 2013 at 15:31
  • and alot more instructions on how to use mount. After that when I use sudo mount --bind etc it says that /mnt/dev for example does not exist
    – Redridge
    Dec 21, 2013 at 15:31
  • There was a typo error so i make a space between sdb1 and / now do it again sudo mount /dev/sdb1/ /mnt
    – Maythux
    Dec 21, 2013 at 15:39
  • now it moutns but it says : mount: mount point /mnt/dev does not exist
    – Redridge
    Dec 21, 2013 at 18:11

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