Talk:GRUB

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Revision as of 05:30, 28 July 2012 by Fengchao (Talk | contribs) (Remove closed topic.)

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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)