UEFI Bootloaders
This page contains info about various UEFI Bootloaders capable of booting Linux kernel. It is recommended to read the UEFI and GPT pages before reading this page. The following bootloaders (listed in decreasing order of stability) are explained here:
Contents
Linux Kernel EFISTUB
Linux (Kernel >= 3.3) supports EFISTUB (EFI BOOT STUB) booting. It is enabled by by default on Arch Linux kernels or can be activated by setting CONFIG_EFI_STUB=y in the Kernel configuration (see The EFI Boot Stub for more information).
A single EFISTUB kernel is not capable of launching other kernels, hence each EFISTUB Kernel + Initramfs pair requires a separate boot menu entry. It is recommended to use a UEFI Boot Manager to manage multiple kernels.
Setting up EFISTUB
- Create a FAT32 UEFI System Partition
- Mount the UEFI System Partition at
/boot/efiwith# mount <UEFI Partition /boot/efi - Create
/boot/efi/EFI/arch/directory with# mkdir /boot/efi/EFI/arch/ - Copy the following files from source to destination
| Boot File Source | UEFI Destination |
|---|---|
| /boot/vmlinuz-linux | /boot/efi/EFI/arch/vmlinuz-linux.efi |
| /boot/initramfs-linux.img | /boot/efi/EFI/arch/initramfs-linux.img |
| /boot/initramfs-linux-fallback.img | /boot/efi/EFI/initramfs-arch-fallback.img |
Sync EFISTUB Kernel
Systemd
Systemd features event triggered tasks. In this particular case, the ability to detect a change in path is used to sync the EFISTUB kernel and initramfs files when they are updated in boot.
[Unit] Description=Copy EFISTUB Kernel to UEFISYS Partition [Path] PathChanged=/boot/vmlinuz-linux PathChanged=/boot/initramfs-linux.img PathChanged=/boot/initramfs-linux-fallback.img [Install] WantedBy=multi-user.target
[Unit] Description=Copy EFISTUB Kernel to UEFISYS Partition [Service] Type=oneshot ExecStart=/bin/cp -f /boot/vmlinuz-linux /boot/efi/EFI/arch/vmlinuz-arch.efi ExecStart=/bin/cp -f /boot/initramfs-linux.img /boot/efi/EFI/arch/initramfs-arch.img ExecStart=/bin/cp -f /boot/initramfs-linux-fallback.img /boot/efi/EFI/arch/initramfs-arch-fallback.img
Incron
incron can run a script to sync the EFISTUB Kernel after updates
#!/bin/sh /bin/cp -f /boot/vmlinuz-linux /boot/efi/EFI/arch/vmlinuz-arch.efi /bin/cp -f /boot/initramfs-linux.img /boot/efi/EFI/arch/initramfs-arch.img /bin/cp -f /boot/initramfs-linux-fallback.img /boot/efi/EFI/arch/initramfs-arch-fallback.img
/boot/initramfs-linux-fallback.img IN_CLOSE_WRITE /usr/local/bin/efistub-update.sh
Mkinitcpio hook
Mkinitcpio can generate a hook that does not need a system level daemon to function. It spawns a background process which waits for the generation of vm-linuz, initramfs-linux.img, and initramfs-linux-fallback.img; then follows step 4 in Setting up EFISTUB
#!/usr/bin/env bash
build() {
local kernel= image=
while getopts ':c:S:' OPT; do
case $OPT in
'c') kernel=$OPTARG;;
'S') image=$OPTARG;;
esac
done
/root/watch.sh $image $kernel &
}
help() {
cat <<HELPEOF
This hook simply waits for mkinitcpio to finish and copies the finished ramdisk and kernel to UEFI
HELPEOF
}
# vim: set ft=sh ts=4 sw=4 et:
#!/bin/bash
EFI_DIR="/boot/efi/EFI/arch"
INITRD=$1
KERNEL=$2
EFI_IMAGE="$EFI_DIR/${KERNEL##*/}.efi"
EFI_INITRD="$EFI_DIR/${INITRD##*/}"
while [[ -d "/proc/$PPID" ]]; do
sleep 1
done
cp $INITRD $EFI_INITRD
cp $KERNEL $EFI_IMAGE
echo "Synced $INITRD to $EFI_DIR"
Booting EFISTUB
One can boot the EFISTUB kernel using one of the following ways :
Using rEFInd
rEFInd is a fork of rEFIt Boot Manager (used in Intel Macs) by Rod Smith (author of GPT-fdisk). rEFInd fixes many issues in rEFIt with respect to non-Mac UEFI booting and also has support for booting EFISTUB kernels and contains some features specific to them. More info about rEFInd support for EFISTUB is at The rEFInd Boot Manager: Methods of Booting Linux.
- Install refind-efi package with
# pacman -S refind-efi - Copy the following files from their source directory to their destination
| rEFInd File Source | UEFI Destination |
|---|---|
| /usr/lib/refind/config/refind.conf | /boot/efi/EFI/refind/refind.conf |
| /usr/share/refind/icons | /boot/efi/EFI/refind/icons |
| /usr/share/refind/docs | /boot/efi/EFI/refind/docs |
| /usr/share/refind/refind_<arch> | /boot/efi/EFI/refind_<arch>.efi |
$esp/EFI/arch/refind_linux.conf
"Boot with defaults" "root=PARTUUID=3518bb68-d01e-45c9-b973-0b5d918aae96 ro rootfstype=ext4 add_efi_memmap systemd.unit=graphical.target" "Boot to Terminal" "root=PARTUUID=3518bb68-d01e-45c9-b973-0b5d918aae96 ro rootfstype=ext4 add_efi_memmap systemd.unit=multi-user.target"
Systemd Automation
#!/bin/bash
## COPYRIGHT 2013 : MARK E. LEE (BLUERIDER) : mlee24@binghamton.edu; mark@markelee.com
## LOG
## 1/17/2013 : Version 2 of refind_name_patch is released
## : Supports long subdirectory location for refind
## : Updates nvram when needed
## : 10% speed boost
function main () { ## main insertion function
declare -r refind_dir="/boot/efi/EFI/refind"; ## set the refind directory
declare -r arch=$(uname -m | awk -F'_' '{if ($1 == "x86"){print $2}}') && ## get bit architecture
update-efi-dir; ## updates or creates the refind directory
update-efi-nvram; ## updates nvram if needed
}
function update-efi-dir () { ## setup the refind directory
if [ ! -d $refind_dir ]; then ## check if refind directory exists
echo "Couldn't find $refind_dir";
mkdir $refind_dir && ## make the refind directory if needed
echo "Made $refind_dir";
fi;
if [ "$arch" ]; then ## check if anything was stored in $arch
cp -r /usr/{share/refind/*,lib/refind/*$arch*} $refind_dir/ && ## update bin and dirs
echo "Updated binaries and directory files for refind at $refind_dir";
else
echo "Failed to detect an x86 architecture";
exit;
fi;
}
function update-efi-nvram () { ## update the nvram with efibootmgr
declare -r ref_bin=${refind_dir/\/boot\/efi}/$(ls /usr/lib | grep $arch*.efi); ## get path of refind binary (without /boot/efi)
declare -r ref_bin_escape=${ref_bin//\//\\\\}; ## insert escape characters into $ref_bin
modprobe efivars && ## grab the efi variables for efibootmgr
efibootmgr -v | grep $ref_bin_escape && ( ## check if boot entry is in nvram
echo "Found boot entry, no need to update nvram";
) || ( ## if boot entry is not in nvram; add it
declare -r esp=$(mount -l | awk '/ESP/ {print $1}') && ## get ESP partition
efibootmgr -c -g -d ${esp:0:8} -p ${esp:8} -w -L "rEFInd" -l $ref_bin_escape && ## update nvram
echo "
Updated nvram with entry rEFInd to boot $ref_bin
Did not copy configuration files, please move refind.conf to $refind_dir/";
)
}
main; ## run the main insertion function
[Unit] Description=Update refind [Path] PathChanged=/usr/lib/refind Unit=refind_update.service [Install] WantedBy=multi-user.target
[Unit] Description=Update refind directories, binaries, and nvram [Service] Type=oneshot ExecStart=/usr/lib/systemd/scripts/refind_name_patchv2 RemainAfterExit=no [Install] WantedBy=multi-user.target
Apple Macs
In case of Apple Macs, try mactel-bootAUR for an experimental "bless" utility for Linux. If that does not work, use "bless" form within OSX to set rEFInd as default bootloader. Assuming UEFISYS partition is mounted at /mnt/efi within OSX, do
$ sudo bless --setBoot --folder /mnt/efi/EFI/refind --file /mnt/efi/EFI/refind/refind_x64.efi
VirtualBox
In case of VirtualBox, see VirtualBox#Using_Arch_under_Virtualbox_EFI_mode.
Using gummiboot
Gummiboot is a UEFI Boot Manager which provides a nice menu for EFISTUB Kernels. It is a new program and relatively untested compared to rEFInd . It is available in [extra] as gummiboot-efi. See http://freedesktop.org/wiki/Software/gummiboot for more info.
Using UEFI Shell
It is possible to launch EFISTUB kernel form UEFI Shell as if it is a normal UEFI application. In this case the kernel parameters are passed as normal parameters to the launched EFISTUB kernel file.
> fs0: > cd \EFI\arch > vmlinuz-arch.efi root=PARTUUID=3518bb68-d01e-45c9-b973-0b5d918aae96 ro rootfstype=ext4 add_efi_memmap initrd=\EFI\arch\initramfs-arch.img
You can also write a simple archlinux.nsh file with your boot parameters and put it in your UEFI System Partition, then run it with:
fs0: archlinux
Example Script:
echo -on \EFI\arch\vmlinuz-arch.efi root=PARTUUID=3518bb68-d01e-45c9-b973-0b5d918aae96 ro rootfstype=ext4 add_efi_memmap initrd=\EFI\arch\initramfs-arch.img
This way you can specify UUID's without needing to remember the name or type out 20-30 characters.
Using efibootmgr entry
It is possible to directly embed the kernel parameters within the boot entry created by efibootmgr. This means that in your BIOS/UEFI you will be able to select Arch Linux directly in the default boot order, and on startup it will boot into Arch directly without any kind of boot selection GUI.
Do (as root):
Install efibootmgr if you haven't already.
# pacman -S --needed efibootmgr
Determine the UUID or PARTUUID of your boot device (ie. the partition for /, not the EFI boot partition)
# blkid
Load the EFI module.
# modprobe efivars
Finally, add the efistub. WARNING: Make sure you replace the following before running this command:
- 3518bb68-d01e-45c9-b973-0b5d918aae96 -- with the UUID of your
/partition. (This is not PARTUUID!) - ext4 -- if you use a different file system.
- /dev/sda -- the drive that contains the EFI boot partition.
- -p 1 -- the partition number of the EFI boot partition.
# echo 'root=UUID=3518bb68-d01e-45c9-b973-0b5d918aae96 ro rootfstype=ext4 add_efi_memmap initrd=\EFI\arch\initramfs-arch.img' | iconv -f ascii -t ucs2 | efibootmgr -c -g -d /dev/sda -p 1 -L "Arch Linux" -l '\EFI\arch\vmlinuz-arch.efi' -@ -
or you can just run the following line (remember to replace /dev/sda1):
# echo "root=UUID=$(blkid /dev/sda1 -o value -s UUID) ro rootfstype=ext4 add_efi_memmap initrd=\\EFI\\arch\\initramfs-arch.img" | iconv -f ascii -t ucs2 | efibootmgr -c -g -d /dev/sda -p 1 -L "Arch Linux" -l '\EFI\arch\vmlinuz-arch.efi' -@ -
More info about efibootmgr at UEFI#efibootmgr. Forum post https://bbs.archlinux.org/viewtopic.php?pid=1090040#p1090040 .
GRUB 2.x
GRUB 2.x contains its own filesystem drivers and does not rely on the firmware to access the files. It can directly read files from /boot and does not require the kernel and initramfs files to be in the UEFISYS partition. Detailed information at GRUB#UEFI_systems_2. For bzr development version try AUR package - grub-efi-x86_64-bzrAUR.
SYSLINUX
Install syslinux-efi-gitAUR AUR package and copy /usr/lib/syslinux/efi64/* to $esp/EFI/syslinux/ ($esp is the mountpoint of UEFISYS partition) (efi64 is for x86_64 UEFI firmwares, replace with efi32 for i386 UEFI firmwares), and then create a boot entry using efibootmgr in the firmware boot manager.
ELILO
ELILO is the UEFI version of LILO Boot Loader. It was originally created for Intel Itanium systems which supported only EFI (precursor to UEFI). It is the oldest UEFI bootloader for Linux. It is still in development but happens at a very slow pace. Upstream provided compiled binaries are available at http://sourceforge.net/projects/elilo/ . Elilo config file elilo.conf is similar to LILO's config file. AUR package - elilo-efi-x86_64AUR (only for x86_64 UEFI).
EFILINUX
EFILINUX is a reference implementation of a UEFI Linux bootloader and precursor to Kenrel EFISTUB support. It is considered to be a alpha quality software (as on 16-MAY-2012). Upstream sources are at https://github.com/mfleming/efilinux . and the usage instructions are at http://thread.gmane.org/gmane.linux.kernel/1172645 and http://article.gmane.org/gmane.linux.kernel/1175060 . AUR packages - efilinux-efi and efilinux-efi-x86_64-gitAUR (only for x86_64 UEFI).
Package Naming Guidelines
UEFI bootloader package(s) should be suffixed with -efi-x86_64 or -efi-i386 to denote package built for 64-bit and 32-bit UEFI respectively. If a single package contains both 64-bit and 32-bit UEFI applications, then -efi suffix should be used in the pkgname.