[lfs-support] Cannot boot to LFS with seperate boot partition

Andrew Elian e_lion_1 at hotmail.com
Thu Jun 21 00:05:45 PDT 2012


Hello,

On Thu, Jun 21, 2012 at 09:43:00AM +0430, Yasser Zamani wrote:
> 
> Hi there,
>  
> When I reboot to LFS with following /etc/fstab and /boot/grub/grub.cfg, 
> after selecting the boot menu, it tells me "error: file not found"

This means that grub (the bootloader) hasn't found the linux kernel.

<snip>
> # Begin /etc/fstab
> # file system  mount-point  type     options             dump  fsck
> #                                                              order
> /dev/sda6     /             ext3     defaults            1     1
> /dev/sda7     /boot         ext3     defaults            1     1

<snip>

> # Begin /boot/grub/grub.cfg
> set default=0
> set timeout=5
> insmod ext3
> set root=(hd0,7)
> menuentry "GNU/Linux, Linux 3.4.1-lfs-SVN-20120617" {
>         linux   /boot/vmlinuz-3.4.1-lfs-SVN-20120617 root=/dev/sda6 ro
> }

<snip>

> Then I tried following /boot/grub/grub.cfg instead; the result was getting two 
> "file not found"s but after pressing key something takes place on screen then 
> the pc halts and CAPS LOCK and NUM LOCK's LEDs are flashing! 
> What do these LEDs flashing mean?

This means that the kernel was found, started running and
then hung. Usually this happens when the kernel doesn't find the root
partition.  It also means that you are a little closer to finding a
solution because this time grub found the linux kernel.

<snip>

> # Begin /boot/grub/grub.cfg
> set default=0
> set timeout=5
> insmod ext3
> set root=(hd0,7)
> menuentry "GNU/Linux, Linux 3.4.1-lfs-SVN-20120617" {
>         linux   /vmlinuz-3.4.1-lfs-SVN-20120617 root=/dev/sda7 ro
> }

<snip>

> Could you please help me to understanding followings:
> Which one takes place at first? Processing and applying 
> /etc/fstab or processing /boot/grub/grub.cfg. If second one takes place at first so how it 
> finds out that where it should look for /boot?

The GRand Unified Bootloader (grub) processes /boot/grub/grub.cfg first.
After the kernel has booted, the system bootscripts read /etc/fstab.

> If above two question's answers can not teach me the solution, so could you please help 
> me to sort this problem out?
> Thanks in advance!

Let's have a look at these lines from your second try:

> set root=(hd0,7)
This line is correct as it tells grub to look for your boot partition.


This next line needs a little tweaking:
>         linux   /vmlinuz-3.4.1-lfs-SVN-20120617 root=/dev/sda7 ro
                  ^^^^^                                     ^^^
                  |                                         |
                  |                                         |
                  |                  This is where I think the error is.
                  This part is good.
root=/dev/XXX should match the root in /etc/fstab.  In your case this would
be /dev/sda6.

Try:
          linux   /vmlinuz-3.4.1-lfs-SVN-20120617 root=/dev/sda6 ro

Also, you will find editing the /boot/grub/grub.cfg easier with vim.
There is a little bit of a learning curve, so finding an online tutorial
is a good idea.

Best of luck!
ae

-- 
My Blog: http://elian001.wordpress.com



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