Difference between revisions of "Talk:GRUB"

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(Grub2 (GPT on non-EFI hardware, meaning on PcBios): new section)
(Grub2 (GPT on non-EFI hardware, meaning on PcBios))
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Just so I remember when I come back to edit the article, grub-install (2.00) currently requires the GRUB_CRYPTODISK_ENABLE environment variable be set to "y". --[[User:Buhman|Buhman]] ([[User talk:Buhman|talk]]) 05:58, 10 October 2012 (UTC)
 
Just so I remember when I come back to edit the article, grub-install (2.00) currently requires the GRUB_CRYPTODISK_ENABLE environment variable be set to "y". --[[User:Buhman|Buhman]] ([[User talk:Buhman|talk]]) 05:58, 10 October 2012 (UTC)
  
== Grub2 (GPT on non-EFI hardware, meaning on PcBios) ==
+
==<s>Grub2 (GPT on non-EFI hardware, meaning on PcBios)</s>==
  
 
There are people who still use PCbios, and it's not going away anytime soon +the fact that drives are getting bigger than 2.2TB..
 
There are people who still use PCbios, and it's not going away anytime soon +the fact that drives are getting bigger than 2.2TB..
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Anybody has done this sort of GPT setup before? It doesn't say how large the unformatted partition has to be on the grub manual, but only if it's large enough..
 
Anybody has done this sort of GPT setup before? It doesn't say how large the unformatted partition has to be on the grub manual, but only if it's large enough..
 +
 +
: actually it is in the [[Grub2#GPT_specific_instructions|wiki]] and the [https://www.gnu.org/software/grub/manual/grub.html#BIOS-installation upstream grub manual]. And yes, doing this is not unprecedented. Please remember to sign your edits to talk pages. --[[User:Buhman|Buhman]] ([[User talk:Buhman|talk]]) 03:27, 25 February 2013 (UTC)

Revision as of 03:27, 25 February 2013

GRUB Legacy stuff should be removed

I mean, seriously, the page is loaded with too much information anyway. And also because of this: http://www.archlinux.org/news/grub-legacy-no-longer-supported/ --DSpider (talk) 17:41, 29 August 2012 (UTC)

EFI

Is there any reason why grub should be installed to /boot/efi/efi/grub and not to /boot/efi? UEFI wants to have the efi-image unter <EFI SYSTEM PARTITION>/efi/name, so /boot/efi/grub should do the trick. Additionally, mounting (e.g.) /dev/sda1 to /boot/efi and just placing the grub there will possibly conflict with having a LVM+LUKS setup, where /boot will then be encrypted. At the moment I'm running a funtoo installation on a thinkpad x121e with /dev/sda1 (200MB, fat32, sectors 1 - 201) mounted to /boot and /dev/sda2 being a LUKS encrypted system. /boot contains the bzImage and /boot/efi/boot/bootx64.efi is the grub-image.

Note: there should possibly be a section/table here containing information what firmware expects what name. having /boot/efi/grub/grub.efi didn't work for me, and as noted in the thinkwiki for an x220, /boot/efi/boot/bootx64.efi works fine. --Rochus 13:59, 16 August 2011 (EDT)


@Rochus: You have mounted your EFISYS partition at /boot ir you are using same part as both EFISYS and /boot and it is FAT32 formatted. The actual path is <EFI_SYS_PART>/efi/grub/grub.efi wherein <EFI_SYS_PART> is usually /boot/efi or in your case /boot itself.

But I do not understand your argument about mounting EFISYS at /boot/efi conflicting with LVM+LUKS. I don't have such a config in my system to understand what you are coming to say. <EFI_SYS_PART>/efi/boot/bootx64.efi is just a fallback path incase there's no boot entry in UEFI Boot Manager (see efibootmgr section). I already mentioned in the article that "If you have mounted EFISYS part at a different mountpoint, replace /boot/efi with that mountpoint in all the commands". I suppose that explains it. It is better to have /boot separate from EFISYS partition. I have /dev/sda1 as 200 MiB FAT32 EFISYS mounted at /boot/efi and /dev/sda3 as 400 MiB ext4 /boot part. For /boot/efi/grub/grub.efi to work you have to add a boot entry to grub.efi in the UEFI Boot Manager using efibootmgr utility. -- Keshav P R 23:15, 28 August 2011 (IST)

GRUB_GFXMODE may not work with a depth parameter

I'm installing on an i5 system with Intel graphics, and found that I could not get a background image if I used any depth parameter in GRUB_GFXMODE=; if I used the 0x value I got the same errors. I would get a black screen with a blue box, titled "Out of Range" and some H. Frequency and V. Frequency parameters. The boot continued in the background, and eventually I got the normal scroll of information during the boot. What I found was that if I just used a resolution, e.g., 800x600, with nothing more, it worked fine. Not sure if this is something for the wiki here or elsewhere, or something to post in the forums; but it should be somewhere to save the next person the hassle of figuring it out, I think. -- Timm 13:08, 29 October 2011 (EDT)

Custom keyboard layout

Hi. Could we add a section explaining how you can set your preferred keyboard layout within GRUB2? As i found here, we need the ckbcomp script, which can be obtained from Debian console-setup package.

Here's how I made things work:

ckbcomp it | grub-mklayout -o /boot/grub/it.gkb

Then, I manually edited /boot/grub/grub.cfg, adding the following lines:

/boot/grub/grub.cfg

terminal_input at_keyboard
keymap (hd0,2)/boot/grub/it.gkb

This worked for me, but as of now, i think it's a very dirty method. Is there some support for keyboard layouts within /etc/default/grub?

Cheers. --Hilinus 12:50, 26 December 2011 (EST)


I followed instructions on the grub-devel mailing list. First you insert

/etc/default/grub

GRUB_TERMINAL_INPUT=at_keyboard

in /etc/default/grub. Then you get ckbcomp Perl script from Ubuntu or Debian and execute (for Slovene layout)

$ ckbcomp si | grub-mklayout -o si.gkb
Unknown key KP_Comma
Unknown key KP_Comma
Unknown key KP_Comma
Unknown key KP_Comma
Unknown keycode 0x79
$ sudo mv si.gkb /boot/grub/

After that you add

/etc/grub.d/40_custom

insmod keylayouts
keymap /boot/grub/si.gkb

to /etc/grub.d/40_custom and finally generate new grub.cfg with

$ sudo grub-mkconfig -o /boot/grub/grub.cfg

Cheers. --drevo 17:47, 6 January 2012 (EST)



The version of ckbcomp I got from Debian Squeeze kept giving this error:

Unknown name $sun_t6_custom

The Ubuntu Precise version worked out of the box.

A temporary solution for layouts would be an AUR package for ckbcomp or to distribute .gkb files somehow, but the proper solution would be for grub-mklayout to accept keymaps(5) files.

--Schizius (talk) 18:44, 26 July 2012 (UTC)

Please make the different options for changing the MBR more clear

The three options here are only separated by a bit unclear titles, and if people follow the links, they might be confused.Jasper1984 (talk) 16:03, 20 July 2012 (UTC)

Backing up grub-legacy bootcode

Both grub2 and grub-legacy write to the space between the end of the MBR and the beginning of the first partition. I'm no expert on this matter; I just learned about it today. That said, it makes me question the usefulness of the dd backup/restore method in the Backup Important Data section. --Alphaniner (talk) 20:07, 25 July 2012 (UTC)

As far as I know, only GRUB2 uses the post-MBR gap. GRUB2 will notice when there is not enough space at the post-MBR gap and return a warning message (without overwriting anything, see [[1]]) 6arms1leg (talk) 15:45, 22 August 2012 (UTC)

GRUB2 + Windows 7 TrueCrypt-encrypted partition

here is a link to my notes from my experience going thru this and Ubuntu Forum post which helped me a GREAT DEAL with this issue - below is a quick HOWTO ::

# ls -al /mnt/win7drive/Users/me/Documents/TrueCrypt\ Rescue\ Disk.iso
   -rwx------ 2 me users 1835008 Sep  5  2011 /mnt/win7/Users/me/Documents/TrueCrypt Rescue Disk.iso
# sudo cp /mnt/win7/Users/me/Documents/TrueCrypt\ Rescue\ Disk.iso /boot/
# mv /boot/TrueCrypt\ Rescue\ Disk.iso /boot/truecryptDesktop.iso
# pacman -S syslinux
# cp /usr/lib/syslinux/memdisk /boot/
# ls -alt /boot
   total 26388
   drwxr-xr-x  5 root root     4096 Jul 29 04:01 .
   -rw-r--r--  1 root root    26140 Jul 29 04:01 memdisk
   -rwx------  1 root root  1835008 Jul 29 03:59 truecryptDesktop.iso
            ....   ....
#mount | grep /boot
   /dev/sda3 on /boot type ext3 (rw,relatime,data=ordered)
# vi /etc/grub.d/40_custom

menuentry "Microsoft Windows 7 x64 Home Premium" {
   insmod part_msdos
   set root='(hd0,msdos3)'
   linux16 ($root)/memdisk iso raw
   initrd16 ($root)/truecryptDesktop.iso
}
# sudo grub-mkconfig -o /boot/grub/grub.cfg

--Fnord0 (talk) 17:59, 30 July 2012 (UTC)

grub-mkconfig with several os

I use several OS (Windows, Arch, Ubuntu, Gentoo) on different partitions. os-prober only found Arch, Windows and Ubuntu -- strangely not Gentoo. But when I mount the gentoo partition, it's found. I don't know, whether this is the case, because I resized the partition, gentoo lives on, or whether this is the `default' behaviour. If so, should the Wiki mention that mounting the partitions help?

--Skunk (talk) 19:46, 30 July 2012 (UTC)

Need simplified steps

I think GRUB2#Preliminary_Requirements_for_GRUB2 part is optional in some cases. If so, it should be noted as optional.

os-prober is quite useful, it should be put at the beginning of the articles, such as preparation.

In my case, I only did the backup, install grub-bios, install os-prober, GRUB2#Install_to_440-byte_MBR_boot_code_region, edit /etc/grub.d/40_custom, and finally grub-mkconfig. My computer is dual-boot with Windows 7.

--Allencch (talk) 00:23, 1 August 2012 (UTC)

encrypted /boot

Just so I remember when I come back to edit the article, grub-install (2.00) currently requires the GRUB_CRYPTODISK_ENABLE environment variable be set to "y". --Buhman (talk) 05:58, 10 October 2012 (UTC)

Grub2 (GPT on non-EFI hardware, meaning on PcBios)

There are people who still use PCbios, and it's not going away anytime soon +the fact that drives are getting bigger than 2.2TB..

There are advantages to GPT that's for sure. But if any of you would update that wiki

->GPT drives+Grub2(non-Efi bootloader)+PcBios

In order for grub2 to boot properly, in this setup, it needs it's own reserved partition. It can be less than 1 meg, as long as big enough to hold <core.img> of grub2. This bios_grub partition can be anywhere on the drive(but for eg, it cannot be inside LVM)

The wiki doesn't say how to make this small unformatted partition, though it mentions about the bios_grub partition.

By least of worry, I simply use 1 megabyte of an unformatted partition, add the bios_grub partition flag, and then install grub to the drive with grub-install.

I use a generic approach to creating this partition for arch and non-arch linux users.. I'm still very new to arch, so I wouldn't know if the parted command is available with it's boot cd.. Having said this I hope it's not intrusive that I tend to use gparted-livecd in order for one to "prep" the drive.. Linux distro installers would fully install for this scenario, but fail to install grub properly

Anybody has done this sort of GPT setup before? It doesn't say how large the unformatted partition has to be on the grub manual, but only if it's large enough..

actually it is in the wiki and the upstream grub manual. And yes, doing this is not unprecedented. Please remember to sign your edits to talk pages. --Buhman (talk) 03:27, 25 February 2013 (UTC)