How to change the keymap (keyboard layout) used by the GRUB shell in Gentoo Linux

The default keymap in the GRUB shell is US English. Because Linux has not yet been booted, the GRUB keymap is not governed by the keymap for the Linux console specified in /etc/conf.d/keymaps in the case of OpenRC, or in /etc/vconsole.conf in the case of systemd. This can be inconvenient if your keyboard has a different layout and you need to use the GRUB Rescue Shell. Below I explain how I configured my Gentoo Linux installation to be able to use a different keyboard layout in the GRUB shell.

There are, however, certain limitations to the keymap in the GRUB shell. The official GRUB documentation states the following:

17.4 Input terminal

Firmware console on BIOS, IEEE1275 and ARC doesn’t allow you to enter non-ASCII characters. EFI specification allows for such but author is unaware of any actual implementations. Serial input is currently limited for latin1 (unlikely to change). Own keyboard implementations (at_keyboard and usb_keyboard) supports any key but work on one-char-per-keystroke. So no dead keys or advanced input method. Also there is no keymap change hotkey. In practice it makes difficult to enter any text using non-Latin alphabet. Moreover all current input consumers are limited to ASCII.

Note that the GRUB documentation states ‘ASCII’, not ‘Extended ASCII’. ASCII is limited to codes 000 to 127 (see the character table in e.g. http://www.asciitable.com/).

Some Linux distributions have the utility grub-kbdcomp to generate a GRUB keyboard layout file. grub-kbdcomp is simply a shell script that is a wrapper for the Debian ckbcomp utility and grub-mklayout. There is a Gentoo Portage ebuild for ckbcomp:

root # eix ckbcomp
[I] sys-apps/ckbcomp
     Available versions:  (~)1.164
     Homepage:            https://anonscm.debian.org/cgit/d-i/console-setup.git
     Description:         Compile an XKB keymap for loadkeys

However, I noticed that the latest version currently available in Debian is 1.191 (https://salsa.debian.org/installer-team/console-setup.git), so I created an ebuild ckbcomp-1.191.ebuild in a local overlay on one of my laptops running Gentoo Linux Stable Branch, and I installed ckbcomp-1.191.

# Copyright 1999-2019 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

EAPI=6

DESCRIPTION="Compile an XKB keymap for loadkeys"
HOMEPAGE="https://salsa.debian.org/installer-team/console-setup.git"

if [[ ${PV} == 9999 ]]; then
        inherit git-r3
        EGIT_REPO_URI="https://salsa.debian.org/installer-team/console-setup.git"
else
        SRC_URI="https://salsa.debian.org/installer-team/console-setup/-/archive/${PV}/${P}.tar.gz -> ${P}.tar.gz"
        KEYWORDS="~amd64"
        S="${WORKDIR}"
fi

LICENSE="GPL-2"
SLOT="0"

DEPEND=""
RDEPEND="
        dev-lang/perl:*
        sys-apps/kbd
        x11-misc/xkeyboard-config"

src_compile() {
        :
}

src_install() {
        dobin console-setup-${PV}-*/Keyboard/ckbcomp
}

I have tried the above-mentioned ckbcomp command on my PC BIOS Core i7 laptop running Gentoo Stable with OpenRC and GRUB Version 2.02-r3:

root # eix -I grub
[I] sys-boot/grub
     Available versions:  (2) 2.02-r3(2/2.02-r3)^st **9999(2/9999)^st
       {debug device-mapper doc efiemu +fonts libzfs mount multislot nls sdl static test +themes truetype GRUB_PLATFORMS="coreboot efi-32 efi-64 emu ieee1275 loongson multiboot pc qemu qemu-mips uboot xen xen-32"}
     Installed versions:  2.02-r3(2/2.02-r3)^st(02:33:36 23/03/19)(fonts nls sdl themes truetype -debug -device-mapper -doc -efiemu -libzfs -mount -multislot -static -test GRUB_PLATFORMS="pc -coreboot -efi-32 -efi-64 -emu -ieee1275 -loongson -multiboot -qemu -qemu-mips -uboot -xen -xen-32")
     Homepage:            https://www.gnu.org/software/grub/
     Description:         GNU GRUB boot loader

I used the following steps:

1. Installed sys-apps/ckbcomp.

root # emerge ckbcomp
root # eix ckbcomp
[I] sys-apps/ckbcomp
     Available versions:  (~)1.164 (~)1.191[1]
     Installed versions:  1.191[1](22:09:15 20/04/19)
     Homepage:            https://salsa.debian.org/installer-team/console-setup.git
     Description:         Compile an XKB keymap for loadkeys

[1] "local_overlay" /usr/local/portage

2. Created a new sub-directory to store the GRUB keyboard layout files.

root # mkdir /boot/grub/layouts

3. Converted the X11 keymap to the GRUB keymap. The option for ckbcomp must exist in the directory /usr/share/X11/xkb/symbols/ for this to work.

root # ckbcomp gb extd | grub-mklayout -o /boot/grub/layouts/gb.gkb
Unknown keyboard scan identifier Meta_Tab
Unknown keyboard scan identifier Meta_Tab
Unknown keyboard scan code 0x54
Unknown keyboard scan code 0x65
Unknown keyboard scan code 0x7f

I used the following commands to generate a br.gkb (Brazilian Portuguese keymap) file and a us.gkb (US English keymap) as well, as it is possible to switch keyboard layouts from the GRUB command line using the keymap command, as I show further on:

root # ckbcomp br nodeadkeys | grub-mklayout -o /boot/grub/layouts/br.gkb
Unknown keyboard scan identifier Meta_Tab
Unknown keyboard scan identifier Meta_Tab
Unknown keyboard scan identifier KP_Comma
Unknown keyboard scan identifier KP_Comma
Unknown keyboard scan identifier KP_Comma
Unknown keyboard scan identifier KP_Comma
Unknown keyboard scan code 0x54
Unknown keyboard scan code 0x65
Unknown keyboard scan code 0x7f
root # ckbcomp us | grub-mklayout -o /boot/grub/layouts/us.gkb
Unknown keyboard scan identifier Meta_Tab
Unknown keyboard scan identifier Meta_Tab
Unknown keyboard scan code 0x54
Unknown keyboard scan code 0x65
Unknown keyboard scan code 0x7f

The resulting files can be seen in the directory /boot/grub/layouts/:

root # ls -la /boot/grub/layouts
total 11
drwxr-xr-x 2 root root 1024 Apr 21 21:20 .
drwxr-xr-x 7 root root 1024 Nov 26 00:01 ..
-rw-r--r-- 1 root root 2572 Apr 21 21:29 br.gkb
-rw-r--r-- 1 root root 2572 Apr 21 21:29 gb.gkb
-rw-r--r-- 1 root root 2572 Apr 21 21:30 us.gkb

4. Append ‘GRUB_TERMINAL_INPUT=at_keyboard‘ to /etc/default/grub.

root # grep GRUB_TERMINAL_INPUT /etc/default/grub
GRUB_TERMINAL_INPUT="at_keyboard"

5. Add ‘insmod‘ and ‘keymap‘ lines to /etc/grub.d/40_custom as shown below.

root # tail -n 2 /etc/grub.d/40_custom
insmod keylayouts
keymap $prefix/layouts/gb.gkb

6. Check what locales are available for the keymap.

root # locale --all-locales | grep -i gb
en_GB
en_GB.iso88591
en_GB.utf8

7. Add ‘locale=en_GB‘ to GRUB_CMDLINE_LINUX.

root # grep locale /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="locale=en_GB i915.modeset=1 rcutree.rcu_idle_gp_delay=1 acpi_enforce_resources=lax reboot=force raid=noautodetect resume=/dev/sda2"

8. Regenerate the grub.cfg file.

root # grub-mkconfig -o /boot/grub/grub.cfg
root # grep terminal_input /boot/grub/grub.cfg
terminal_input at_keyboard
root # grep gkb /boot/grub/grub.cfg
keymap $prefix/layouts/gb.gkb
root # grep layouts /boot/grub/grub.cfg
insmod keylayouts
keymap $prefix/layouts/gb.gkb

9. If the machine uses UEFI rather than PC BIOS, update the GRUB files in the EFI directory.

root # grub-install --efi-directory=/boot/efi

10. Reboot to check if the gb keymap has been loaded for the GRUB shell.

root # reboot

When I press ‘c‘ when the GRUB menu appears, I now see the following if I press each key on the second-to-last row of keys on the keyboard:

grub> \zxcvbnm,./

That corresponds to a British English keyboard layout. As I mentioned before, due to GRUB’s limitations only standard ASCII chars are possible, so it is not possible to type characters such as é and è, or symbols such as £ and etc. on the GRUB command line, whatever the keymap.

You can tell if the GRUB keylayouts module is loaded by entering the following command on the GRUB command line:

lsmod

Below is what I then see on the screen of a PC BIOS machine running up-to-date Gentoo Linux (Stable Branch) when I press ‘c‘ when the GRUB menu is displayed.


                                                GNU GRUB  version 2.02~beta3

   Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists possible device or file completions. ESC at any time exits.


grub> lsmod
Name    Ref Count       Dependencies
minicmd 1
gfxterm_background      1              bitmap,video,extcmd,gfxterm,bitmap_scale,video_colors
bitmap_scale    2               bitmap
video_colors    2
png     1               bitmap,bufio
bitmap  7
search  1               search_label,extcmd,search_fs_file,search_fs_uuid
search_label    2
search_fs_file  2
search_fs_uuid  2
at_keyboard     1               boot,keylayouts
keylayouts      3
gfxterm 3               video,font
all_video       1               video_cirrus,video_bochs,vga,vbe
video_cirrus    2               video_fb,pci,video
video_bochs     2               video_fb,pci,video
pci     6
vga     2               video_fb,video
vbe     2               video_fb,video
video_fb        12
font    5               video,bufio
video   24
loadenv 1               extcmd,disk
disk    2
test    1
normal  1               gettext,boot,extcmd,bufio,crypto,terminal
gzio    0
gettext 3
boot    4
extcmd  8
bufio   10
crypto  2
terminal        2
biosdisk        1
part_msdos      2
ext2    4               fshelp
fshelp  5
grub>

Shown below is what I see when I perform the following steps on the GRUB command line:

  1. press each key on the second-to-last line of keys on the keyboard and press Enter;
  2. check which GRUB terminal input module is loaded;
  3. change from the British English keyboard layout to the Brazilian Portuguese keyboard layout;
  4. press each key on the second-to-last line of keys on the keyboard and press Enter;
  5. switch back to the British English keyboard layout;
  6. press each key on the second-to-last line of keys on the keyboard and press Enter;
  7. switch to the US English keyboard layout;
  8. press each key on the second-to-last line of keys on the keyboard and press Enter;
  9. switch back to the British English keyboard layout.

In each case the output on the screen is correct for the keyboard layout selected:

grub> \zxcvbnm,./
error: can't find command `zxcvbnm,./'.
grub> terminal_input
Active input terminals:
at_keyboard
Available input terminals:
console serial_* serial
grub> keymap br
grub> \zxcvbnm,.;
error: can't find command `zxcvbnm,.;'.
grub> keymap gb
grub> \zxcvbnm,./
error: can't find command `zxcvbnm,./'.
grub> keymap us
grub> <zxcvbnm,./
error: syntax error.
error: Incorrect command.
error: syntax error.
grub> keymap gb
grub> 

There is one more caveat…

When the GRUB menu first appears at boot, the following lines are still displayed at the bottom of the GRUB menu:

   Use the ↑ and ↓ keys to select which entry is highlighted.
   Press enter to boot the selected OS, `e' to edit the commands before booting or `c' for a command-line.
The highlighted entry will be executed automatically in 4s.

However, the highlighted entry on the GRUB menu is no longer executed automatically and I have to press ENTER in order to get GRUB to boot Linux. That is not a big deal in my case.

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The best way to dual boot Linux and Windows

I’m going to explain how to configure your PC in order to dual boot Linux and Windows Vista or Windows 7, assuming Windows is already installed.

If you already have Windows Vista or Windows 7 installed in a single partition, then the method described below is the best way of ensuring that your Windows installation will still be bootable even if the Linux installation or GRUB bootloader become damaged in future.

Furthermore, if your PC has a hidden factory restore partition for Windows, the method described below is the best way of ensuring that you will still be able to recover Windows in future using that hidden partition. The reason why this is the best method is because it does not alter the contents of the MBR (Master Boot Record), which, in addition to the Windows bootloader, may contain code created by the manufacturer to boot the hidden factory restore partition instead of the Windows Vista/7 partition if it detects that you pressed a defined key or keys while the PC is booting. If the contents of the original MBR are overwritten — even if it is only by using the Bootrec.exe tool on a standard Windows Vista/7 Installation DVD — then the manufacturer’s code will no longer be in the MBR and so it will no longer be possible to boot the hidden factory restore partition by pressing the key(s) specified by the manufacturer.

Note also that some Windows applications can make a PC using GRUB 2 unbootable if GRUB 2 is installed in the MBR. See the blog article Windows applications making GRUB 2 unbootable for details. The method described below does not install any GRUB 2 code in the MBR, and thus it will avoid this problem.

So, to reiterate, the method described below avoids two potential major problems: 1) it avoids the possibility of making a Windows factory restore partition unusable; 2) it avoids the possibility of Windows applications overwriting some of the GRUB 2 code.

If you already have Windows installed, the procedure to prepare the PC and install Linux is divided into the following three main stages.

Stage 1: Reduce the size of the existing Windows partition

Do not use the partition managers Parted, GParted or KDE Partition Manager to reduce the size of the existing Windows partition, or you will damage your Windows installation.

Step A: Use the Windows defragmenter or a third-party defragmenter to defragment the Windows partition.

Step B: Use Windows’ Disk Management to shrink the partition (see Resize a Partition for Free in Windows 7 or Vista). The problem with this method is that Windows will only shrink the partition until it reaches the MFT (Master File Table), which means there may be free space in the Windows partition that you would have wanted to use in a Linux partition but cannot. However, if you are satisfied with the resulting size of the Windows partition then you can skip Step C below and proceed directly to Stage 2.

Step C: If you cannot shrink the Windows partition to the size you want by using Windows’ Disk Management, then you need to move the MFT (see Working Around Windows Vista’s “Shrink Volume” Inadequacy Problems). Basically you need to download a tool such as PerfectDisk (it has a free trial period) that will defragment the Windows partition and move the MFT in the process.

Stage 2: Create the new partitions for Linux

Boot a LiveCD or LiveDVD which has the partition editor GParted on it, and run GParted to create and format partitions for Linux (for example /, /boot, /home and swap) in the free space you created in Stage 1 above. I prefer to use GParted to create the partitions before running the Linux distribution’s installer, rather than using a partitioning tool integrated into the Linux installer itself. GParted has more functionality and enables better control over the partitioning process than a partitioning tool incorporated in the Linux distribution’s installer. Also, I have found on some occasions that installation of some Linux distributions fails if using the partitioning tool integrated in the Linux installer, but is successful if the partitions were created beforehand.

SystemRescueCD is a good LiveCD to use for running GParted, but any LiveCD/DVD which includes GParted will suffice. You can download the ISO file from the SystemRescueCd Web site http://www.sysresccd.org/Main_Page.

It is only possible to have up to four primary partitions on a hard disk, so, depending on the Linux partitions you decide to create, it is possible that you will need to create an extended partition containing logical partitions. If, for example, your hard disk has a hidden Windows factory restore partition and a partition for Windows itself, and you decide you want to have /boot and /home on separate partitions to the root directory, then one of many possible partitioning schemes would be:

– the hidden Windows factory restore partition (a Primary partition)

– the Windows partition (a Primary partition)

– the /boot partition (a Primary partition)

– an Extended partition containing the following Logical partitions:

– the swap partition

– the / (root) partition

– the /home partition

For example, on my main laptop I created and formatted the partitions /dev/sda3 to /dev/sda7 as follows:

/dev/sda1 – the hidden Windows factory restore partition

/dev/sda2 – the Windows C: drive partition

/dev/sda3 – the Linux /boot partition

/dev/sda4 – an Extended partition containing the following Logical partitions:

/dev/sda5 – the swap partition

/dev/sda6 – the / (root) partition

/dev/sda7 – the /home partition

Note that it is not essential to have /boot, / and /home in different partitions; they could all be in the same partition. However, I would recommend that at least /home be given a separate partition, so that personal files (videos, music, documents, etc.) would not be overwritten if you were to re-install Linux at some point.

You are free to choose your own partitioning scheme, but I create the Linux partitions in the order shown above so that I can assign specific sizes to the /boot, swap and / partitions, leaving the remainder of the disk space free for the /home partition.

If you do decide to put /boot on its own partition, it only needs to be small (I make it around 100 MB). On my laptop the /dev/sda4 Extended partition is around 143 GB so I created a partition of 60 GB for / (root) — which is more than ample — and a partition for /home using the rest of the available space on the laptop’s 320 GB hard disk. You’ll have to decide on the size of these partitions based on the size of the hard disk and the root partition’s space requirements recommended by the Linux distribution’s developers.

If you do not need Linux to be able to hibernate (‘suspend-to-disk’) then a swap partition of 512 MB would be sufficient for the typical desktop PC, especially when the latest PCs come with 4 GB or more RAM. Some people do not even bother having a swap partition at all with such large amounts of RAM. But if you do want Linux to be able to hibernate then try to find out if the Linux kernel which you will be installing was compiled with in-kernel LZO compression algorithm support (LZO compression algorithm support must not be compiled as a module). If the kernel was compiled with in-kernel LZO compression algorithm support then make the size of the swap partition the same as the RAM size, which is more than enough. For example, as my laptop has 4 GB of RAM I created /dev/sda5 as a 4 GB partition. If LZO compression algorithm support was not compiled into the kernel and you do not know how to rebuild the kernel after installing Linux then you will have to make the swap partition bigger than your RAM size (my guess would be at least 1.5 times the size to be on the safe side).

As to the choice of file system, I format /boot, / and /home as ext4 but you can choose a different native Linux file system if you want. You cannot use Windows’ FAT or NTFS for these Linux partitions.

Stage 3: Install the GRUB bootloader and Linux

Boot Windows Vista/7 and download the freeware tool EasyBCD from the NeoSmart Web site (you might like to make a small donation, to help the developer). You will need to download EasyBCD version 2 and upwards if you want to install a Linux distribution that uses GRUB 2; it is available to download from http://neosmart.net/dl.php?id=1. If you are going to install a Linux distribution that uses GRUB Legacy then the current version of EasyBCD should work too. Follow the instructions on the EasyBCD site on how to install Linux (http://neosmart.net/wiki/display/EBCD/Linux). N.B. You will reach a point in the Linux installation process when the Linux installer allows you to make a choice of where to install the GRUB bootloader: in the MBR (Master Boot Record) of the HDD or in the first sector of the Linux boot partition. You must select the latter, not the MBR. If the Linux installer offers you the option of installing GRUB to e.g. /dev/sda then that would install GRUB in the MBR, because no partition is specified. Make sure you specify the partition that will contain the /boot directory (/dev/sda3 in my particular case). If you created a separate partition for /boot then GRUB will be installed on that separate partition, whereas if you did not create a separate partition for /boot then GRUB will be installed on the partition containing the root directory.

The result of Stage 3 will be that, when you boot your PC, the Windows Vista/7 bootloader will load the GRUB bootloader, and the GRUB bootloader will load Linux. This process is called ‘chainloading’. When you boot the PC you will first see the Windows bootloader menu, and you can select Windows or Linux from it. If you select Linux then you will see the GRUB menu and you can select Linux from that menu, which will boot the distribution.

Whilst chainloading GRUB 2 from the Windows bootloader is more long-winded than booting GRUB 2 directly, you can now use Linux and Windows safe in the knowledge that GRUB 2 will not be overwritten by any Windows applications, and that a Windows factory restore partition will be bootable in an emergency.

A corner case

EDIT (June 21, 2012): A note about a ‘corner case’. This will only apply to a very small minority of users, and then probably only to some users of Gentoo Linux (in Gentoo Linux it is possible to have both /boot/grub/ and /boot/grub2/ simultaneously). If you select ‘GRUB2’ in the pull-down menu in the current version of EasyBCD (2.1.2), EasyBCD actually searches the sub-directories under /boot/ to find the GRUB 2 core.img file, and puts an entry in the Windows BCD pointing directly to that file, i.e. EasyBCD ignores the boot sector of the Linux boot partition. Therefore, when you select ‘Linux’ in the Windows boot manager’s menu, the Windows boot manager does not launch the GRUB code in the boot sector of the partition on which /boot/ resides, it launches the core.img file directly. Now, if your boot partition happens to have both the sub-directories /boot/grub/ and /boot/grub2/, and they both contain a GRUB 2 file core.img, EasyBCD 2.1.2 will create a BCD entry pointing to the one under /boot/grub/ rather than the one under /boot/grub2/. This may or may not be what you want. If you want GRUB 2 to use the core.img under /boot/grub2/, the workaround in EasyBCD 2.1.2 is to select ‘GRUB Legacy’ in the EasyBCD pull-down menu and specify the boot partition. This is counter-intuitive, but it forces EasyBCD to create an entry in the BCD that points to the boot sector of the boot partition instead of the core.img file in a sub-directory of /boot/ on that partition. The GRUB 2 code in the partition’s boot sector will then execute the core.img file in the required sub-directory. This workaround only works if the Linux boot partition is on the same drive as the Windows partition. The developer of EasyBCD will be updating EasyBCD to look for a core.img file in /boot/grub2/ before /boot/grub/, rather than the other way around, if they both exist when you select ‘GRUB2’ in the EasyBCD pull-down menu.

EDIT (September 5, 2012): The EasyBCD developer has fixed EasyBCD a) to cater for core.img being either in /boot/grub2/i386-pc/ or in /boot/grub/, and b) to look for core.img in /boot/grub2/ before looking for it in /boot/grub/. The version with the fix, EasyBCD 2.2 Beta – Build 179.exe or later, can be downloaded from NeoSmart Technologies’ EasyBCD Support Forum. I’ve tried it and it works!

EDIT (January 28, 2015): In October 2013 the GRUB 2 directory in Gentoo was changed from /boot/grub2/ to /boot/grub/, so the above two comments are redundant and you can ignore them.

Make sure you read the EasyBCD FAQ page

EDIT (September 5, 2012): Make sure you read the EasyBCD FAQ page. For example, it states that, to date, EasyBCD does not support the EFI/UEFI, only the traditional PC BIOS.

EDIT (December 18, 2013): According to the NeoSmart Knowledgebase: “As of EasyBCD 2.2, EFI/UEFI and GPT disks are fully supported, but some options may not be compatible with EFI machines.“. I have not tried Version 2.2 or above of EasyBCD with EFI/UEFI and GPT disks, so cannot corroborate this.

EDIT (June 26, 2015): Make sure the partition containing the Linux boot directory is a Primary partition, not a Logical partition. This is because of a Windows limitation.