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I am running ubuntu 14.04 on my machine with following partition structure:

/boot 512MB
/     50G
swap  4G
/home 100G~

and I have another drive which has slackware 14.1 on it with following structure:

/boot 512M (with working initrd)
(encrypted lvm containing /, swap and home )

I want to know if there is a way i can add my slackware system to ubuntu's grub, so that i will be able to boot both operating systems (multi-bootish way).

I tried adding something like following to /boot/grub/grub.cfg:

menuentry "Slackware" { 
      linux /dev/sdb2/vmlinux 
      initrd /dev/sdb2/initrd.gz
}

and to /etc/default/grub:

GRUB_DISALBE_OS_PROBE=true

but when i run grub-update it gets cleared.

I have some knowledge of LILO but grub is quite new for me so any kind of help is greatly appreciated.

Thanks.

-Update: Thanks oldfred, got it working by doing following:

sudo apt-get update && sudo apt-get install lvm2 cryptsetup
sudo modprobe dm-crypt
sudo cryptsetup luksOpen /dev/sdb2 my-crypt
sudo os-prober
sudo update-grub

going to try the menuentry thing also though.

user7011
  • 13
  • I think os-prober should be enabled in /etc/default/grub. And changes made to /boot/grub/boot.cfg are vanished with update-grub, so if you want to add menu entries you'll have to do it in /etc/grub.d/40_custom. And I don't know if the /dev/sdb1/vmlinux syntax will work with GRUB, it's better to use GRUB's syntax (hdX,Y). – Eduardo Cola Feb 01 '16 at 16:11

1 Answers1

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Lilo is a Windows type boot loader. So may be easier to chain load to the MBR or PBR of your other drive.

This is a partition boot entry. But note that drive you boot from is always hd0 in grub, but drive order can otherwise vary.

How to add a GRUB2 menu entry for booting installed Ubuntu on a USB drive?

menuentry "Install on sda (When from sdc) Chainboot" {
set root=(hd1)
chainloader +1
}

menuentry "Install on sdb (from sdc) Chainboot" {
set root=(hd2)
chainloader +1
}

menuentry "Chainload Other Systems Grub Menu on sdc1" {
set root=(hd2,1)
chainloader +1
}


menuentry " " {
set root= 
}

menuentry "System restart" {
echo "System rebooting..."
    insmod reboot
reboot
}    

menuentry "System shutdown" {
echo "System shutting down..."
    insmod halt
halt
}

Correct entry to turn off os-prober

Turn off prober

gksudo gedit /etc/default/grub

Add this line

GRUB_DISABLE_OS_PROBER=true

update grub menu after any change

sudo update-grub

If using LVM you make be able to get os-prober to work if you add the lvm drivers in Ubuntu and manually mount the encrypted partition (so it is unencrypted) when os-prober runs.

sudo apt-get update && sudo apt-get install lvm2 cryptsetup

If other steps to mount & unencrypt needed they are here, just you do not need all the resize instructions: https://help.ubuntu.com/community/ResizeEncryptedPartitions

Community
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oldfred
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