Grub 2 Basics

[dariusdwtt]

Hope I'm not repeating something, that someone else already said, but I thought it would be of value to mention, that if you have Win 7 or XP, on the same PC and it will boot, you could use grud24dos.

Install it on the MS OS and then you will have a "virtual grub", that you can use to boot into any other OS that you lost, and then follow the usual procedures to restore grub from your other OS.

No need to boot from any other media.
No need to write to the mbr.
No need to burn discs.
No need to download isos.
Grub will be compatible.

and I'm sure there are a bunch of other good reasons.

[drs305]

Hope I'm not repeating something, that someone else already said, but I thought it would be of value to mention, that if you have Win 7 or XP, on the same PC and it will boot, you could use grud24dos.

Install it on the MS OS and then you will have a "virtual grub", that you can use to boot into any other OS that you lost, and then follow the usual procedures to restore grub from your other OS.

No need to boot from any other media.
No need to write to the mbr.
No need to burn discs.
No need to download isos.
Grub will be compatible.

and I'm sure there are a bunch of other good reasons.

Thanks for sharing. Is it really 'grud24dos'? I notice you spelled it the same in another thread. Do you have a link that you've used for this - Windows users would probably like to investigate it.

[dariusdwtt]

LOL, soz yes grub.

There's a link in the previous post, and here is a link to the readme.

You'll just need to know which partition your installation is on.

[ratcheer]

Maybe this question has already been answered, but I can't read through 82 pages of posts to try to find it.

I needed to set the nomodeset parameter for a second Linux on my PC. I prefer grub2 (Arch uses legacy grub), so I control the booting configuration from Ubuntu. If I add the parameter to /etc/default/grub and run update-grub, the only boot command that is affected is the one for Ubuntu.

Therefore, to achieve the needed effect, I had to manually edit /boot/grub/grub.cfg, which is a no-no for grub2. I am uncomfortable with this. Is the main problem that I will have to make this manual change after every time update-grub is run? Is there a better way to do this?

Thanks,
Tim

[zika]

Maybe this question has already been answered, but I can't read through 82 pages of posts to try to find it.

I needed to set the nomodeset parameter for a second Linux on my PC. I prefer grub2 (Arch uses legacy grub), so I control the booting configuration from Ubuntu. If I add the parameter to /etc/default/grub and run update-grub, the only boot command that is affected is the one for Ubuntu.

Therefore, to achieve the needed effect, I had to manually edit /boot/grub/grub.cfg, which is a no-no for grub2. I am uncomfortable with this. Is the main problem that I will have to make this manual change after every time update-grub is run? Is there a better way to do this?

Thanks,
Tim

If You have ATI card

sudo echo options radeon modeset=0 > /etc/modprobe.d/radeon-kms.conf

might do the trick...

[ratcheer]

Thanks, @zika. Can I use that even if I'm using fglrx instead of the rafeon driver?

For some reason, fglrx in Arch requires nomodeset, but in Ubuntu, it does not. Unless Ubuntu is doing something hidden to invoke nomodeset, but it does not show up in grub2.

Tim

[zika]

Thanks, @zika. Can I use that even if I'm using fglrx instead of the rafeon driver?

For some reason, fglrx in Arch requires nomodeset, but in Ubuntu, it does not. Unless Ubuntu is doing something hidden to invoke nomodeset, but it does not show up in grub2.

Tim

I do not think so... I think this is only for OpenSource driver... I'm not sure...

[drs305]

I needed to set the nomodeset parameter for a second Linux on my PC. I prefer grub2 (Arch uses legacy grub), so I control the booting configuration from Ubuntu. If I add the parameter to /etc/default/grub and run update-grub, the only boot command that is affected is the one for Ubuntu.

Therefore, to achieve the needed effect, I had to manually edit /boot/grub/grub.cfg, which is a no-no for grub2. I am uncomfortable with this. Is the main problem that I will have to make this manual change after every time update-grub is run? Is there a better way to do this?

I can think of two ways to accomplish this.

The first is to create a custom menuentry for the second OS. You would copy the entire menuentry of the one you want to change into /etc/grub.d/40_custom. Then add the kernel option to the 'linux' line.

To make the entry 'survive' new kernel updates to that Linux OS, if the structure is the same as Ubuntu, you could even change the linux line section "/boot/vmlinuz-2.6..." to "/vmlinuz" and the 'initrd' line from "/boot/initrd.img-2.6...." to "/initrd.img".

The second way would be to modify the 30_os-prober script so that it automatically adds the kernel option to Linux OSs found by the prober script. If you only have one OS found by os-prober, this could be pretty simple. If you have multiple OSs and only need it on one, the change would be a bit more complicated but still achievable. If you want this option I can give you more info.

[ratcheer]

Thank you, drs305. I am going to closely look at the second method you suggested. Hopefully, I will be able to give it a try.

Tim

PS - I examined the script. Could I just append ' nomodeset' to the line for Linux that says 'linux ${LKERNEL} ${LPARAMS}' ?

[drs305]

Thank you, drs305. I am going to closely look at the second method you suggested. Hopefully, I will be able to give it a try.

Tim

PS - I examined the script. Could I just append ' nomodeset' to the line for Linux that says 'linux ${LKERNEL} ${LPARAMS}' ?

Hehe. I just opened a reply and it included your addition, which is what I was just about to post.

Yes, it's line 237 in Grub 1.99. It will be attached to every linux entry in the 30_os-prober section.

If you need any other help, just ask.


Added:
If you need it only for a specific partition, use a conditional with $LROOT (ex. /dev/sda9 ), for a particular OS, $LABEL (Ubuntu). At least that is what the variables were when I first played with G2.