Grub 2 Basics

[peter b]

@ drs305,

scenario, jaunty with grub2 1.96 installed and working ok1 with all previous kernels as well as karmic.

just installed in karmic grub2 (1.97 beta4) and updated --> everything ok, all kernels 'seen'. however,

sudo grub-install /dev/sda

that's MBR not run. how safe is the last 1.97 beta4 ?

should I run it or hold a little longer ?

thanks.

[drs305]

that's MBR not run. how safe is the last 1.97 beta4 ?
should I run it or hold a little longer ?

I am not sure I understand that first part. If jaunty was also on sda I would say it is very safe. If jaunty was on another device I would still run the command - especially since all your G2 menus have installed without issue so far. Of course, that's just one opinion.

[peter b]

yes, jaunty and the other kernels, karmic included, are all on sda (logical part) with/had their own PBR. grub2 1.96 upgrade brought MBR in my situation into the play.

[drs305]

yes, jaunty and the other kernels, karmic included, are all on sda (logical part) with/had their own PBR. grub2 1.96 upgrade brought MBR in my situation into the play.

Grub2 can be installed in a partition but it will complain first and isn't recommended. The reason is that it uses blocklists and the system is subject to failure if things change position on the drive/partition. The chances of this are probably much higher than having problems from installing Grub 2 to the MBR.

[n6yga]

So, what is the trick to get 40_custom entries to load? The file, 40_custom is set to execute, I have disabled 30_os-prober, but the custom file is nerver "read." I am at my wits end!!

What the hell am I forgetting?

Here is the 40_custom file:

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.

echo "Adding Arch Linux" >$2
menuentry "Arch Linux" {
	set root=(hd2,1)
	linux /vmlinuz26 root=/dev/sdg2 ro
	initrd /kernel26.img
}

menuentry "Arch Linux Fallback" {
	set root=(hd2,1)
	linux /vmlinuz26 root=/dev/sdg2 ro
	initrd /kernel26-fallback.img
}

Thanks,
Mark.

[RedSquirrel]

So, what is the trick to get 40_custom entries to load? The file, 40_custom is set to execute, I have disabled 30_os-prober, but the custom file is nerver "read." I am at my wits end!!

What the hell am I forgetting?

Did you run:

sudo update-grub

Then have a look at /boot/grub/grub.cfg to see if your Arch entries are there.

By the way, you should remove that echo command OR move it to the top of the file and increment the tail command line number, like this:

#!/bin/sh
echo "Adding Arch Linux" >$2
exec tail -n +4 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.


menuentry "Arch Linux" {
    set root=(hd2,1)
    linux /vmlinuz26 root=/dev/sdg2 ro
    initrd /kernel26.img
}

menuentry "Arch Linux Fallback" {
    set root=(hd2,1)
    linux /vmlinuz26 root=/dev/sdg2 ro
    initrd /kernel26-fallback.img
}

[ranch hand]

Your origan entries look prefect. Except you need to ADD one thing to each of them;

echo "Adding Arch Linux" >$2
menuentry "Arch Linux" {
    set root=(hd2,1)
    linux /vmlinuz26 root=/dev/sdg2 ro
    initrd /kernel26.img
}
EOF

That "EOF" addeed to both of them and running "sudo update-grub" should do it.

Let us know.

[RedSquirrel]

Your origan entries look prefect. Except you need to ADD one thing to each of them;

echo "Adding Arch Linux" >$2
menuentry "Arch Linux" {
    set root=(hd2,1)
    linux /vmlinuz26 root=/dev/sdg2 ro
    initrd /kernel26.img
}
EOF

That "EOF" addeed to both of them and running "sudo update-grub" should do it.

The EOF is not needed in this case. That is only required when you used the cat command. See my earlier post here.

[n6yga]

Well, it turns out that the file was being added to grub.cfg. What's weird is I can boot the initrd for Arch, but Arch craps out looking for either the UUID of the root partition, or the "/dev/sdg2." Both of which are correct.

I may just try chainloading to Arch on the external USB drive.

Thanks, guys!

Mark.

[tjl30]

The new version of grub through me off a little, but after reading this guide I am defiantly a fan of Grub 2.

Great guide very easy to follow!