[SOLVED] Booting into linux when your boot sector is gone?

pljvaldez · 10-26-2009, 02:32 PM

You probably need to open a root shell instead of a user shell. Your prompt should be like root@knoppix#:

Avatar · 10-27-2009, 11:16 AM

Here are the results

Code:

root@Microknoppix:/# mkdir /mnt/temp
root@Microknoppix:/# mount /dev/sda5 /mnt/temp
root@Microknoppix:/# chroot /mnt/temp
[root@Microknoppix /]# lilo -b /dev/sda5
Ignoring entry 'boot'
Warning: '/proc/partitions' does not exist, disk scan bypassed
Added linux-secure
Added linux
Added linux-nonfb
Added failsafe
Fatal: open /dev/hda1: No such device or address
[root@Microknoppix /]#

Does that mean installing LILO worked, and the error is just because I've removed hda1 (the IDE drive?) or did the whole thing fail.

How can I use my Knoppix CD to get into my Mandrake Desktop? thanks!

pljvaldez · 10-27-2009, 11:37 AM

From the chroot environment, what did your /etc/fstab look like? I suspect that error is associated with that. Did you also edit the lilo.conf file before you ran lilo -b? You'll have to modify it to boot the partition now that the /dev/hda is gone.

Avatar · 10-27-2009, 02:59 PM

I did not edit lilo.conf or anything else, I only typed the commands you gave me...

Here is the output, interestingly my W2K/Mandrake drive is labelled as hdc, and not sda? Yet it is the same physical drive?

Code:

[root@Microknoppix /]# cat /etc/fstab
/dev/hdc5 / ext3 defaults 1 1
none /dev/pts devpts mode=0620 0 0
/dev/hdc7 /home ext3 defaults 1 2
/dev/hdb /mnt/cdrom auto user,noauto,ro 0 0
/dev/fd0 /mnt/floppy auto user,codepage=850,noauto,sync,iocharset=iso8859-15,exec 0 0
/dev/hda1 /mnt/win_c vfat codepage=850,iocharset=iso8859-15 0 0
/dev/hdc1 /mnt/win_c2 ntfs ro,iocharset=iso8859-15 0 0
none /proc proc defaults 0 0
/dev/hdc6 swap swap defaults 0 0

[root@Microknoppix /]# cat /etc/lilo.conf
boot=/dev/hda
map=/boot/map
# vga=normal
default="Win2K_Server"
keytable=/boot/us.klt
prompt
nowarn
timeout=200
message=/boot/message
menu-scheme=wb:bw:wb:bw
image=/boot/vmlinuz-secure
	label="linux-secure"
	root=/dev/hdc5
	initrd=/boot/initrd-secure.img
	append="devfs=mount acpi=ht resume=/dev/hdc6 splash=silent"
	read-only
image=/boot/vmlinuz
	label="linux"
	root=/dev/hdc5
	initrd=/boot/initrd.img
	append="devfs=mount acpi=ht resume=/dev/hdc6 splash=silent"
	vga=788
	read-only
image=/boot/vmlinuz
	label="linux-nonfb"
	root=/dev/hdc5
	initrd=/boot/initrd.img
	append="devfs=mount acpi=ht resume=/dev/hdc6"
	read-only
image=/boot/vmlinuz
	label="failsafe"
	root=/dev/hdc5
	initrd=/boot/initrd.img
	append="failsafe devfs=nomount acpi=ht resume=/dev/hdc6"
	read-only
other=/dev/hda1
	label="Windows_ME"
	table=/dev/hda
other=/dev/hdc1
	label="Win2K_Server"
	table=/dev/hdc
	map-drive=0x80
	   to=0x81
	map-drive=0x81
	   to=0x80
[root@Microknoppix /]#

pljvaldez · 10-27-2009, 05:16 PM

Sorry. Old versions of linux handled SATA and IDE drives differently than today. Assuming that this is a SATA drive (which you mentioned above), my guess is that you will want to change your fstab to look like this:

Code:

/dev/sda5 / ext3 defaults 1 1
none /dev/pts devpts mode=0620 0 0
/dev/sda7 /home ext3 defaults 1 2
/dev/hdb /mnt/cdrom auto user,noauto,ro 0 0
/dev/fd0 /mnt/floppy auto user,codepage=850,noauto,sync,iocharset=iso8859-15,exec 0 0
#/dev/hda1 /mnt/win_c vfat codepage=850,iocharset=iso8859-15 0 0 <-- You removed this drive
/dev/sda1 /mnt/win_c2 ntfs ro,iocharset=iso8859-15 0 0
none /proc proc defaults 0 0
/dev/sda6 swap swap defaults 0 0

I would probably from the chroot environment do a cp /etc/fstab /etc/fstab.old so you have a backup copy to mess with if you need it. Then you can modify /etc/fstab. You can either remove or comment out the /dev/hda1 line since you removed that drive.

Then make a copy of lilo.conf the same way (cp /etc/lilo.conf /etc/lilo.conf.old) and edit it to look like this:

Code:

boot=/dev/sda5
map=/boot/map
# vga=normal
default="Win2K_Server"
keytable=/boot/us.klt
prompt
nowarn
timeout=200
message=/boot/message
menu-scheme=wb:bw:wb:bw
image=/boot/vmlinuz-secure
	label="linux-secure"
	root=/dev/sda5
	initrd=/boot/initrd-secure.img
	append="devfs=mount acpi=ht resume=/dev/sda6 splash=silent"
	read-only
image=/boot/vmlinuz
	label="linux"
	root=/dev/sda5
	initrd=/boot/initrd.img
	append="devfs=mount acpi=ht resume=/dev/sda6 splash=silent"
	vga=788
	read-only
image=/boot/vmlinuz
	label="linux-nonfb"
	root=/dev/sda5
	initrd=/boot/initrd.img
	append="devfs=mount acpi=ht resume=/dev/sda6"
	read-only
image=/boot/vmlinuz
	label="failsafe"
	root=/dev/sda5
	initrd=/boot/initrd.img
	append="failsafe devfs=nomount acpi=ht resume=/dev/sda6"
	read-only
#other=/dev/hda1
#	label="Windows_ME"
#	table=/dev/hda
other=/dev/sda1
	label="Win2K_Server"
	table=/dev/sda
#	map-drive=0x80
#	   to=0x81
#	map-drive=0x81
#	   to=0x80

You can comment out/delete the /dev/hda1 lines for ME again. You probably won't need the map-drive functions for Win2k since this will be the primary drive now.

You may also need to look at the file /boot/map that gets called in the beginning of lilo.conf.

Anyway, when you're done editing lilo.conf, you run the lilo -b command to install it to the / partition. Then you need to create a boot floppy or use another bootloader to chainload it. I like XOSL on floppy or CD. It's got a nice intuitive graphical interface.

Avatar · 10-28-2009, 10:37 AM

That was an awesome post, thanks for the detail, it helped. Everything went well this time:

Code:

[root@Microknoppix /]# lilo -b /dev/sda5
Ignoring entry 'boot'
Warning: '/proc/partitions' does not exist, disk scan bypassed
Added linux-secure
Added linux
Added linux-nonfb
Added failsafe
Added Win2K_Server *

However, I couldn't figure out how to install XOSL to a floppy; it seems to be something you install on your hard disk.

I am wondering if it would be possible to make a GRUB boot floppy disk (I found instructions) from Knoppix, and use that to boot the LILO installed on /dev/sda5?

pljvaldez · 10-28-2009, 11:41 AM

Yup, you could do that to.

Your menu.lst file should look something like this

Code:

title Mandrake
root (hd0,4)
chainloader +1
boot

Grub counts hard disks and partitions starting from zero. So the first drive (sda) should be hd0. The first partition would be partition 0. So sda1 = (hd0,0), sda2 = (hd0,1), etc. which makes sda5 = (hd0,4).

Avatar · 10-28-2009, 11:53 AM

Well, it worked!
I didn't know how to do the menu.lst so I typed in the commands at the prompt and it worked great. It got me over to lilo on my Mandrake 9.2 (!) install.

I was very happy to see my old Mandrake loading screen.

Only problem now is I'm encountering a kernel panic (no init found) so now that I'm that far I can look into how to resolve that.

Thank you for all your help.

Avatar · 10-29-2009, 11:34 AM

Turns out you cannot edit a Mandrake lilo from Knoppix

Knoppix was seeing my drive as sda while Mandrake was seeing it as hdc. So I couldn't update my LILO from within Knoppix.

Managed to find my original install CD (from 2003!) and set it up that way. Now I can boot in. Thanks for the help!