EFIBootLoaders

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Revision 5 as of 2013-09-23 18:15:38
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Revision 6 as of 2021-02-08 13:17:16
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UEFI defines a new method of interfacing between PC operating systems and firmware. The UEFI interface is composed of data tables containng platform-related information, plus boot and runtime functions that are available to the operating system and the boot loader. These provide a standard environment for booting and running pre-boot applications.  UEFI defines a new method of interfacing between PC operating systems and firmware. The UEFI interface is composed of data tables containng platform-related information, plus boot and runtime functions that are available to the operating system and the boot loader. These provide a standard environment for booting and running pre-boot applications.
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The table following lists known features found in current EFI/UEFI capable boot loaders and boot managers. (Note: Boot managers present a menu of boot options, whereas boot loaders load a kernel. Many programs can do both tasks, although rEFIt and rEFInd can load a kernel only if it includes an EFI stub loader.) The table following lists known features found in current EFI/UEFI capable boot loaders and boot managers. (Note: Boot managers present a menu of boot options, whereas boot loaders load a kernel. Many programs can do both tasks, although rEFIt can load a kernel on PC hardware only if it includes an EFI stub loader.)
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Y - feature known to exist, Yes - feature known to exist,
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blank - feature does not exist No - feature does not exist
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||||||||<tablestyle="width: 90%">'''UEFI/EFI Bootloader Features'''|| || || '''BIOS Bootloader'''||
||
||<:17%> '''ELILO''' ||<:17%> '''Grub 2''' ||<:17%> '''Kernel EFI stub loader''' ||<:17%> '''rEFIt''' ||<:17%> '''rEFInd''' ||<:17%>'''Grub 0.97'''||
||<v>'''Feat
ures''' ||LILO like EFI boot loader, originally developed for IA-64 by HP, now with IA-32 support || Grub 2 with EFI support || Boot loader built into 3.3.0 and later kernels; turns the kernel into its own boot loader || EFI graphical boot manager, originally for Apple Macs|| EFI graphical boot manager, forked from rEFIt because of rEFIt's apparent abandonment || BIOS Only ||
||Graphical boot manager || || Y || || Y || Y || Background ||
|| JPG images || || Y || || || || ||
|| BMP images || || || || Y || Y || ||
|| PNG images || || Y || || || || ||
|| XPM images ||
|| ? ||   || || || Y ||
|| ICNS images
|| || ? ||  || Y || Y || ? ||
||Text boot manager || Y || Y || || Y || Y || Y ||
||Mouse support || || || || || || ||
||Config file || Y|| Y || || Y || Y || Y ||
||specify kernel image || Y|| Y || || || Y || Y ||
||interactive mode || Y|| Y || || || || Y ||
||load initrd || Y|| Y || Y || || Y || Y ||
||kernel selector menu || Y|| Y || || || Y || Y ||
||kernel boot params || Y|| Y || Y || || Y || ||
||Boot once and then revert to previous kernel || Y || || || || || ||
||Variables to paramaterize boot e.g. root=/dev/nfs ip=%I:%z:%G:%N|| Y || || || || || ||
||Enable legacy BIOS || || ? || || Y || Y || '''BIOS ONLY''' ||
||Chain loading || || Y || || Y || Y || Y ||
||Gzip compression support || || Y || Y || || Y || Y ||
||Load ELF binaries || || Y || || || || Y ||
||IA-64 || Y || ? || Y || || ?
|| ||
||x86-32 || Y || Y || Y || Y || Y || Y ||
||x86-64 || Y || Y || Y || Y || Y || Y ||
||Apple fat image || || || || Y || || ||
||Boot unmodified linux kernel || Y || Y || Y || || Y || Y ||
||Relocate Kernel ||IA-64 modified kernel|| || || || || ||
||Load FPSWA driver (Floating Point Software Assist) || Y (IA-64 only) || || || || || N/A ||
||Font Support || Y || Y || || || || ? ||
||'''File System Support:'''    || || || || || || ||
|| AFFS || || Y || || || || ||
|| AFS || || Y || || || || ||
|| Btrfs || || Y || || || Y || ||
|| CPIO || || Y || || || || ||
|| FAT || Y || Y || Y || Y || Y || Y ||
|| EXT2 || Y || Y || Y || Y || Y || Y ||
|| EXT3 || Y || Y || Y || Y || Y || Y ||
|| EXT4 || || Y || || || Y || Y (Jaunty+) ||
|| FFS || || Y || || || || Y ||
|| HFS || || Y || || || || ||
|| HFSPLUS || Y || Y || Y || Y || Y || ||
|| ISO9660 || Y || Y || Y || Y || Y || Y ||
|| JFS || || Y || || || || Y ||
|| MINIX || || Y || || || || Y ||
|| NTFS || || Y || || || || ||
|| NTFSCOMP || || Y || || || || ||
|| REISERFS || Y || Y || Y || Y || Y || Y ||
|| SFS (Amiga) || || Y || || || || ||
|| UDF || || Y || || || || ||
|| UFS || || Y || || || || Y ||
|| XFS || || Y || || || || Y ||
||NOTE: || ELILO loads kernel + initrd using EFI, hence only supports VFAT or, via EFI drivers, ext2, ext3, ext4, ReiserFS, Btrfs, HFS+, or ISO
-9660 || || Same comment as for ELILO || Same comment as for ELILO || Same comment as for ELILO || ||
||
'''Disk Volume/Partition Support:'''|| || || || || || ||
|| RAID || || Y || || || || Y ||
|| LVM || || Y || || || || Y ||
|| ADFS (Acorn) partition maps || || Y || || || || ||
|| Amiga Patition Tables || || Y || || || || ||
|| Macintosh Partition Tables || || Y || || || || ||
|| PC (MBR) Partition Tables || || Y || Y || Y || Y || Y ||
|| Sun Partition Tables || || Y || || || || ||
|| GPT (GUID Partition Tables) (UEFI)|| Y || Y || Y || Y || Y ||
|| Disk Loopback || || Y || || || || ||
|| Find filesystems by UUID or label|| || Y || || || || Y (Intrepid+)||
||'''Commands''' || || Y || || || || ||
|| background || || || || || || Y ||
|| beep sound PC speaker || || Y || || || || ||
|| print file block list || || Y || || || || Y ||
|| set border colour || || || || || || Y ||
|| cat files || || Y || || || || Y ||
|| clear screen || || || || || || Y ||
|| compare files || || Y || || || || Y ||
|| cpu ID || || Y || || || || ||
|| debug mode || Y || || || || || Y ||
|| display APM BIOS info || N/A || N/A || || N/A || N/A || N/A || Y ||
|| display memory info || || || || || || Y ||
|| dump file (copy) || || || || || || Y ||
|| echo / print || || Y || || || || Y ||
|| fallback to known kernel || || || || || || Y ||
|| find a file on partitions || || || || || || Y ||
|| file system test mode || || || || || || Y ||
|| help || || Y || || || || Y ||
|| print geometry of disk || || || || || || Y ||
|| manually load config file || || Y || || || || ||
|| halt machine || || Y || || Y || Y || Y ||
|| hide a partition || || || || || || Y ||
|| hexdump a file || || Y || || || || ||
|| intel multiprocessor probe || || || || || || Y ||
|| i/o port probe a drive || || || || || || Y ||
|| load/save environment variables|| || Y || || || || ||
|| ls files || || Y
|| || || || ||
|| lspci || || Y || || || || ||
|| make a drive bootable || || || || || || Y ||
|| map one drive to another || || || || || || Y ||
|| screen pager || || || || || || Y ||
|| partition manipulation || || || || || || Y ||
|| pause/sleep || || Y || || || || Y ||
|| read variables from user input|| || Y || || || || ||
|| read memory address || || || || || || Y ||
|| reboot computer || || Y || || Y || Y || ||
|| select terminal || || Y || || || || ||
|| serial console support || || || || || || Y ||
|| set keyboard mappings || || || || || || Y ||
|| expression handling || || Y || || || || ||
|| video testing || || Y || || || || ||
|| list vbe modes || || Y || || || || Y ||
|| vbe test || || Y || || || || ||
|| load font files || || Y || || || || ||
|| block users from using EFI shell || || || || Y || Y || ||
|| disable booting from optical drive || || || || Y || Y || ||
|| disable booting from internal drives|| || || || Y || Y || ||
|| block apple HW testing || || || || Y || Y || ||
||
'''Toolchain Contraints''' || || || || || || || ||
||IA-64: gcc version ||3.1, 3.2|| ? || ? || ? || ? || ? ||
||IA-64: binutils ||2.13.90 || ? || ? || ? || ? || ? ||
||x86-32: gcc-version ||3.2 || ? || ? || ? || ? || ? ||
||x86-32: binutils ||2.13.90.0.2 || ? || ? || ? || ? || ? ||
||x86-64: gcc-version ||4.1.1+ || ? || ? || ? || ? || ? ||
||x86-64: bintil ||2.17.50.0.14+ || ? || ? || ? || ? || ? ||
||'''Netboot''' || || || || || || || ||
|| PXE || Y || || || || || ||
|| DCHP || Y || || || || || Y ||
|| TFTP || Y || || || || || Y ||
|| BOOTP || || || || || || Y ||
|| IFCONFIG || ? || || || || || Y ||
|| RARP || || || || || || Y ||
||<tablewidth="90%"|3> '''Features''' ||<:-3> '''EFI/UEFI Bootloaders''' ||<:-3> '''EFI/UEFI Boot Managers''' ||<:14%> '''BIOS Bootloader''' ||
||<:14%> '''ELILO''' ||<:14%> '''GRUB 2''' ||<:14%> '''Kernel stub loader''' ||<:14%> '''rEFIt''' ||<:14%> '''rEFInd''' ||<:14%> '''systemd-boot''' ||<:> '''GRUB 0.97''' ||
||<:> Oldest/most stable Linux
EFI bootloader, very limited features ||<:> Most complex Linux EFI bootloader available, actively developed ||<:> Linux kernels since v3.3.0 are bootable via system firmware; no bootloader needed ||<:> EFI graphical boot manager, development stopped in 2010 ||<:> EFI graphical boot manager with OS auto-detection, semi-active development ||<:> EFI text-menu boot manager with modern features but very simple interface, actively developed ||<:> No EFI/UEFI support; included for comparison only ||
||Graphical interface mode ||<:#ff9999> No ||<:#99ff99> Yes ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ffff99> Background imgs only ||
||Mouse support ||<:#ff9999> No ||<:#ff9999> No ||<:#ff9999> No ||<:#ff9999> No ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||
||Text menu interface mode ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
|| JPG images ||<:#ff9999> No ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ececec> ? ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||
|| BMP images ||<:#ff9999> No ||<:#ff9999> No ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||
|| PNG images ||<:#ff9999> No ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||
|| XPM images ||<:#ff9999> No ||<:#ececec> ? ||<:#ff9999> No ||<:#ff9999> No ||<:#ff9999> No ||<:#ff9999> No ||<:#99ff99> Yes ||
|| ICNS images ||<:#ff9999> No ||<:#ececec> ? ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ececec> ? ||
||File-based configuration ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||select from multiple kernels ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||interactive mode ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||load initrd ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||kernel selector menu ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||kernel boot params ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec> ? ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||Boot old kernel if upgrade fails ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||Paramaterize kernel cmdline opts<<FootNote(e.g. root=/dev/nfs ip=%I:%z:%G:%N, where the utility can generate the needed values based on information it can probe for)>> ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||<:#ff9999> No ||<:#99ff99> Yes ||<:#ff9999> No ||<:#ff9999> No ||
||Enable legacy BIOS || || ? || || Y || Y || || '''BIOS ONLY''' ||
||Chain loading || || Y || || Y || Y || || Y ||
||Gzip compression support || || Y || Y || || Y || || Y ||
||Load ELF binaries || || Y || || || || || Y ||
||
IA-64           || Y || ? || Y || || ? || || ||
||x86-32 || Y || Y || Y || Y || Y ||   || Y ||
||x86-64 || Y || Y || Y || Y || Y ||   || Y ||
||Apple fat image || || || || Y || || ||   ||
||Boot unmodified linux kernel || Y || Y || Y || || Y || || Y ||
||Relocate Kernel ||IA-64 modified kernel|| || || || || || ||
||Load FPSWA driver (Floating Point Software Assist) || Y (IA-64 only) || || || || ||   || N/A ||
||Font Support || Y || Y || || || ||   || ? ||
||<:-8> '''File System Support:'''<<FootNote(Loading of kernel+initrd occurs using EFI firmware, hence only supports FAT16/32 (but if given 3rd-party EFI drivers can then read: ext2, ext3, ext4, ReiserFS, Btrfs, HFS+, or ISO-9660))>> ||
|| AFFS || || Y || || || || ||   ||
|| AFS || || Y || || || || ||   ||
|| Btrfs || || Y || || || Y || || ||
|| CPIO || || Y || || || || ||   ||
|| FAT || Y || Y || Y || Y || Y || || Y ||
|| EXT2 || Y || Y || Y || Y || Y ||   || Y ||
|| EXT3 || Y || Y || Y || Y || Y ||   || Y ||
|| EXT4 || || Y || || || Y ||   || Y (Jaunty+) ||
|| FFS || || Y || || || ||   || Y ||
|| HFS || || Y || || || || || ||
|| HFSPLUS || Y || Y || Y || Y || Y || ||   ||
|| ISO9660 || Y || Y || Y || Y || Y ||   || Y ||
|| JFS || || Y || || || || || Y ||
|| MINIX || || Y || || || ||   || Y ||
|| NTFS || || Y || || || || || ||
|| NTFSCOMP || || Y || || || || ||   ||
|| REISERFS || Y || Y || Y || Y || Y ||   || Y ||
|| SFS (Amiga) || || Y || || || || ||   ||
|| UDF || || Y || || || || ||   ||
|| UFS || || Y || || || ||   || Y ||
|| XFS || || Y || || || ||   || Y ||
||<:
-8> '''Disk Volume/Partition Support:''' ||
|| RAID || || Y || || || ||   || Y ||
|| LVM || || Y || || || || || Y ||
|| ADFS (Acorn) partition maps || || Y || || || || ||   ||
|| Amiga Patition Tables || || Y || || || || ||   ||
|| Macintosh Partition Tables || || Y || || || || || ||
|| PC (MBR) Partition Tables || || Y || Y || Y || Y ||   || Y ||
|| Sun Partition Tables || || Y || || || || || ||
|| GPT (GUID Partition Tables)  || Y || Y || Y || Y || || Y ||<:#ff9999> No ||
|| Disk Loopback || || Y || || || || || ||
|| Find filesystems by UUID or label|| || Y || || || ||   || Y (Intrepid+)||
||'''Commands''' || || Y || || || || ||   ||
|| background || || || || || ||   || Y ||
|| beep sound PC speaker || || Y || || || || ||   ||
|| print file block list || || Y || || || ||   || Y ||
|| set border colour || || || || || ||   || Y ||
|| cat files || || Y || || || ||   || Y ||
|| clear screen || ||    || || || || || Y ||
|| compare files || || Y  || || || || || Y ||
|| cpu ID || || Y || || || || ||   ||
|| debug mode || Y ||    || || || || || Y ||
|| display APM BIOS info || N/A || N/A || || N/A || N/A ||   || Y ||
|| display memory info || ||    || || || || || Y ||
|| dump file (copy) || || || || || ||   || Y ||
|| echo / print || || Y || || || ||   || Y ||
|| fallback to known kernel || || || || || ||   || Y ||
|| find a file on partitions || || || || || ||   || Y ||
|| file system test mode || || || || || ||   || Y ||
|| help || || Y || || || ||   || Y ||
|| print geometry of disk || || || || || ||   || Y ||
|| manually load config file || || Y  || || || || || ||
|| halt machine || || Y || || Y || Y ||   || Y ||
|| hide a partition || ||    || || || || || Y ||
|| hexdump a file || || Y || || || || ||   ||
|| intel multiprocessor probe || || || || || ||   || Y ||
|| i/o port probe a drive || ||    || || || || || Y ||
|| load/save environment variables|| || Y || || || ||  || ||
|| ls files || || Y ||
|| || || || ||
|| lspci || || Y || || || || ||   ||
|| make a drive bootable || || || || || ||   || Y ||
|| map one drive to another || || || || || ||   || Y ||
|| screen pager || ||    || || || || || Y ||
|| partition manipulation || || || || || ||   || Y ||
|| pause/sleep || || Y  || || || || || Y ||
|| read variables from user input|| || Y || || || || ||   ||
|| read memory address || ||    || || || || || Y ||
|| reboot computer || || Y || || Y || Y || ||   ||
|| select terminal || || Y  || || || || || ||
|| serial console support || || || || || ||   || Y ||
|| set keyboard mappings || || || || || ||   || Y ||
|| expression handling || || Y || || || || ||   ||
|| video testing || || Y  || || || || || ||
|| list vbe modes || || Y || || || ||   || Y ||
|| vbe test || || Y || || || || ||   ||
|| load font files || || Y  || || || || || ||
|| block users from using EFI shell || || || || Y || Y || ||   ||
|| disable booting from optical drive || || || || Y || Y || ||   ||
|| disable booting from internal drives|| || || || Y || Y  || || ||
|| block apple HW testing || || || || Y || Y || ||   ||
||<:-8>
'''Toolchain Contraints''' ||
||IA-64: gcc version ||3.1, 3.2|| ? || ? || ? || ? ||   || ? ||
||IA-64: binutils ||2.13.90 || ? || ? || ? || ?  || || ? ||
||x86-32: gcc-version ||3.2 || ? || ? || ? || ? ||   || ? ||
||x86-32: binutils ||2.13.90.0.2 || ? || ? || ? || ? ||   || ? ||
||x86-64: gcc-version ||4.1.1+ || ? || ? || ? || ? || || ? ||
||x86-64: bintil ||2.17.50.0.14+ || ? || ? || ? || ? ||   || ? ||
||<:-8> '''Netboot Methods:''' ||
|| PXE || Y || || ||    || || || ||
|| DCHP || Y || || || || ||   || Y ||
|| TFTP || Y || || || ||    || || Y ||
|| BOOTP || || ||    || || || || Y ||
|| IFCONFIG || ? || || || || ||  || Y ||
|| RARP || || || || || ||  || Y ||

<<BR>> '''Footnotes:''' <<BR>>
<<FootNote>>
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All EFI executable images contain a PE/COFF header defining the format of the executable code.  All EFI executable images contain a PE/COFF header defining the format of the executable code.
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    CONFIG_EFI_VARS=y or m # optional      CONFIG_EFI_VARS=y or m # optional

EFI/UEFI Boot Loaders

UEFI defines a new method of interfacing between PC operating systems and firmware. The UEFI interface is composed of data tables containng platform-related information, plus boot and runtime functions that are available to the operating system and the boot loader. These provide a standard environment for booting and running pre-boot applications.

The table following lists known features found in current EFI/UEFI capable boot loaders and boot managers. (Note: Boot managers present a menu of boot options, whereas boot loaders load a kernel. Many programs can do both tasks, although rEFIt can load a kernel on PC hardware only if it includes an EFI stub loader.)

Key: Yes - feature known to exist, ? - cannot determine, No - feature does not exist

Features

EFI/UEFI Bootloaders

EFI/UEFI Boot Managers

BIOS Bootloader

ELILO

GRUB 2

Kernel stub loader

rEFIt

rEFInd

systemd-boot

GRUB 0.97

Oldest/most stable Linux EFI bootloader, very limited features

Most complex Linux EFI bootloader available, actively developed

Linux kernels since v3.3.0 are bootable via system firmware; no bootloader needed

EFI graphical boot manager, development stopped in 2010

EFI graphical boot manager with OS auto-detection, semi-active development

EFI text-menu boot manager with modern features but very simple interface, actively developed

No EFI/UEFI support; included for comparison only

Graphical interface mode

No

Yes

No

Yes

Yes

No

Background imgs only

Mouse support

No

No

No

No

Yes

No

No

Text menu interface mode

Yes

Yes

No

Yes

Yes

Yes

Yes

JPG images

No

Yes

No

?

Yes

No

No

BMP images

No

No

No

Yes

Yes

No

No

PNG images

No

Yes

No

No

Yes

No

No

XPM images

No

?

No

No

No

No

Yes

ICNS images

No

?

No

Yes

Yes

No

?

File-based configuration

Yes

Yes

No

Yes

Yes

Yes

Yes

select from multiple kernels

Yes

Yes

No

Yes

Yes

Yes

Yes

interactive mode

Yes

Yes

No

No

Yes

Yes

Yes

load initrd

Yes

Yes

Yes

Yes

Yes

Yes

Yes

kernel selector menu

Yes

Yes

No

Yes

Yes

Yes

Yes

kernel boot params

Yes

Yes

Yes

?

Yes

Yes

Yes

Boot old kernel if upgrade fails

Yes

Yes

No

No

Yes

Yes

Yes

Paramaterize kernel cmdline opts1

Yes

No

No

No

Yes

No

No

Enable legacy BIOS

?

Y

Y

BIOS ONLY

Chain loading

Y

Y

Y

Y

Gzip compression support

Y

Y

Y

Y

Load ELF binaries

Y

Y

IA-64

Y

?

Y

?

x86-32

Y

Y

Y

Y

Y

Y

x86-64

Y

Y

Y

Y

Y

Y

Apple fat image

Y

Boot unmodified linux kernel

Y

Y

Y

Y

Y

Relocate Kernel

IA-64 modified kernel

Load FPSWA driver (Floating Point Software Assist)

Y (IA-64 only)

N/A

Font Support

Y

Y

?

File System Support:2

AFFS

Y

AFS

Y

Btrfs

Y

Y

CPIO

Y

FAT

Y

Y

Y

Y

Y

Y

EXT2

Y

Y

Y

Y

Y

Y

EXT3

Y

Y

Y

Y

Y

Y

EXT4

Y

Y

Y (Jaunty+)

FFS

Y

Y

HFS

Y

HFSPLUS

Y

Y

Y

Y

Y

ISO9660

Y

Y

Y

Y

Y

Y

JFS

Y

Y

MINIX

Y

Y

NTFS

Y

NTFSCOMP

Y

REISERFS

Y

Y

Y

Y

Y

Y

SFS (Amiga)

Y

UDF

Y

UFS

Y

Y

XFS

Y

Y

Disk Volume/Partition Support:

RAID

Y

Y

LVM

Y

Y

ADFS (Acorn) partition maps

Y

Amiga Patition Tables

Y

Macintosh Partition Tables

Y

PC (MBR) Partition Tables

Y

Y

Y

Y

Y

Sun Partition Tables

Y

GPT (GUID Partition Tables)

Y

Y

Y

Y

Y

No

Disk Loopback

Y

Find filesystems by UUID or label

Y

Y (Intrepid+)

Commands

Y

background

Y

beep sound PC speaker

Y

print file block list

Y

Y

set border colour

Y

cat files

Y

Y

clear screen

Y

compare files

Y

Y

cpu ID

Y

debug mode

Y

Y

display APM BIOS info

N/A

N/A

N/A

N/A

Y

display memory info

Y

dump file (copy)

Y

echo / print

Y

Y

fallback to known kernel

Y

find a file on partitions

Y

file system test mode

Y

help

Y

Y

print geometry of disk

Y

manually load config file

Y

halt machine

Y

Y

Y

Y

hide a partition

Y

hexdump a file

Y

intel multiprocessor probe

Y

i/o port probe a drive

Y

load/save environment variables

Y

ls files

Y

lspci

Y

make a drive bootable

Y

map one drive to another

Y

screen pager

Y

partition manipulation

Y

pause/sleep

Y

Y

read variables from user input

Y

read memory address

Y

reboot computer

Y

Y

Y

select terminal

Y

serial console support

Y

set keyboard mappings

Y

expression handling

Y

video testing

Y

list vbe modes

Y

Y

vbe test

Y

load font files

Y

block users from using EFI shell

Y

Y

disable booting from optical drive

Y

Y

disable booting from internal drives

Y

Y

block apple HW testing

Y

Y

Toolchain Contraints

IA-64: gcc version

3.1, 3.2

?

?

?

?

?

IA-64: binutils

2.13.90

?

?

?

?

?

x86-32: gcc-version

3.2

?

?

?

?

?

x86-32: binutils

2.13.90.0.2

?

?

?

?

?

x86-64: gcc-version

4.1.1+

?

?

?

?

?

x86-64: bintil

2.17.50.0.14+

?

?

?

?

?

Netboot Methods:

PXE

Y

DCHP

Y

Y

TFTP

Y

Y

BOOTP

Y

IFCONFIG

?

Y

RARP

Y


Footnotes:

  1. e.g. root=/dev/nfs ip=%I:%z:%G:%N, where the utility can generate the needed values based on information it can probe for (1)

  2. Loading of kernel+initrd occurs using EFI firmware, hence only supports FAT16/32 (but if given 3rd-party EFI drivers can then read: ext2, ext3, ext4, ReiserFS, Btrfs, HFS+, or ISO-9660) (2)

Booting from EFI

All EFI compliant systems have an EFI System Partition (ESP), which is a FAT32 partition containing EFI firmware modules and boot images. Note that there can be one or more system partions. The ESP is effectively the boot partition, and contains the necessary images to boot a system. This boot partition should probably be mounted on a Linux system as /boot/efi for the updating of new kernels and initrd images.

Each vendor "must" use a dedicated directory in \EFI\vendor for the .efi bootloader code.

nshell is the EFI shell. It will execute the boot script called startup.nsh found in the root of an ESP. startup.nsh can be used to load and execute the preferred boot loader. More commonly, a list of boot loaders is maintained in NVRAM variables called Boot####, where #### is a hexadecimal number. The boot order is maintained in the BootOrder variable. These variables can be manipulated in Linux with the efibootmgr utility. If the NVRAM contains no such entries or if they're all invalid, recent EFI implementations default to using a boot loader of the form \EFI\BOOT\boot{arch}.efi, where {arch} is an architecture code, such as "x64" for x86-64 or "ia32" for x86.

All EFI executable images contain a PE/COFF header defining the format of the executable code. The code may be one of:

  • IA-32
  • x86-64 (aka X64)
  • Itaninum
  • ARM
  • Processor agnostic generic EFI byte code

ELILO, the kernel's EFI stub loader, Grub 2 (with EFI support), rEFIt, and rEFInd are all processor native executable code.

KERNEL configuration

Build the kernel with the following configuration.

    CONFIG_FB_EFI=y
    CONFIG_FRAMEBUFFER_CONSOLE=y

If EFI runtime services are expected, the following configuration should be selected.

    CONFIG_EFI=y
    CONFIG_EFI_VARS=y or m          # optional

To use the EFI stub loader, you must set the following option:

    CONFIG_EFI_STUB=y

The kernel can then be loaded from an EFI shell or by entering it into the EFI's boot list in NVRAM. Getting the options right can be tricky, though. Using rEFInd to launch a kernel with EFI stub support can simplify matters.

References

EFIBootLoaders (last edited 2023-12-07 18:11:36 by roguescholar)