Diff for "EFIBootLoaders"

EFIBootLoaders

Differences between revisions 4 and 9 (spanning 5 versions)

Contents

EFI/UEFI Boot Loaders
1. Comparison table
Booting from EFI
KERNEL configuration
External Links

EFI/UEFI Boot Loaders

Legend
Yes	Feature known to exist
?	Indeterminate feature presence
No	Feature does not exist

UEFI defines a new method of interfacing between PC operating systems and firmware. The UEFI interface is composed of data tables containing 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.)

Comparison table

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; 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
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	?	?	No	Yes	Yes	No	BIOS ONLY
Chain loading	No	Yes	No	Yes	Yes	Yes	Yes
Gzip compression support	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Load ELF binaries	Yes	Yes	No	Yes	Yes	Yes	Yes
Apple fat image	?	?	?	Yes	?	?	?
Boot unmodified linux kernel	Yes	Yes	Yes	?	Yes	Yes	Yes
Relocate Kernel	No	Yes	No	No	Yes	Yes	Yes
IA-64 modified kernel	Yes	Yes	Yes	?	?	?	?
Load FPSWA driver²	Yes (IA-64 only)	?	?	?	?	?	N/A
Custom font support	Yes	Yes	No	Yes	Yes	No	?
Architecture Support:
x86-64	Yes	Yes	Yes	Yes	Yes	?	Yes
x86-32	Yes	Yes	Yes	Yes	Yes	?	Yes
IA-64	Yes	Yes	Yes	?	?	?	?
File System Support:³
Amiga FFS	?	Yes	?	?	Yes	?	?
AFS	?	Yes	?	?	Yes	?	?
Btrfs	?	Yes	?	?	Yes	?	?
CPIO	?	Yes	?	?	Yes	?	?
EXT2	Yes	Yes	Yes	Yes	Yes	Yes	Yes
EXT3	Yes	Yes	Yes	Yes	Yes	Yes	Yes
EXT4	?	Yes	?	?	Yes	Yes	Yes (Jaunty+)
FAT	Yes	Yes	Yes	Yes	Yes	Yes	Yes
FFS	?	Yes	?	?	No	?	Yes
HFS	?	Yes	?	?	Yes	?	?
HFS+	Yes	Yes	Yes	Yes	Yes	?	?
ISO9660	Yes	Yes	Yes	Yes	Yes	?	Yes
JFS	?	Yes	?	?	Yes	?	Yes
MINIX	?	Yes	?	?	Yes	?	Yes
NTFS	?	Yes	?	?	Yes	?	?
NTFS Compressed	?	Yes	?	?	?	?	?
ReiserFS	Yes	Yes	Yes	Yes	Yes	Yes	Yes
SFS (Amiga)	?	Yes	?	?	Yes	?	?
UDF	?	Yes	?	?	Yes	?	?
UFS	?	Yes	?	?	Yes	?	Yes
XFS	?	Yes	?	?	Yes	?	Yes
ZFS	?	?	?	?	Yes	?	?
Disk Volume/Partition Support:
RAID	?	Yes	?	?	?	?	Yes
LVM	?	Yes	?	?	Yes	?	Yes
ADFS (Acorn partition maps)	?	Yes	?	?	?	?	?
Amiga partition tables	?	Yes	?	?	?	?	?
Macintosh partition tables	?	Yes	?	?	?	?	?
Master Boot Record (MBR) tables	?	Yes	Yes	Yes	Yes	?	Yes
Sun partition tables	?	Yes	?	?	?	?	?
GPT (GUID partition tables)	Yes	Yes	Yes	Yes	Yes	Yes	No
Disk loopback	?	Yes	?	?	?	?	?
Filesystems by UUID/Label	?	Yes	?	?	Yes	?	Yes (Intrepid+)
Image File Format Support:
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	?
Command Line Operations
background	?	?	?	?	?	?	Yes
beep (PC speaker)	?	Yes	?	?	?	?	?
print file block list	?	Yes	?	?	?	?	Yes
set border color	?	?	?	?	?	?	Yes
read text file contents	?	Yes	?	?	Yes	?	Yes
clear screen	?	?	?	?	?	?	Yes
compare files	?	Yes	?	?	?	?	Yes
identify CPU	?	Yes	?	?	?	?	?
debug mode	Yes	?	?	?	?	?	Yes
display APM BIOS info	N/A	N/A	?	N/A	N/A	?	Yes
display RAM info	?	?	?	?	?	?	Yes
dump file (copy)	?	?	?	?	?	?	Yes
echo / print	?	Yes	?	?	?	?	Yes
fallback to known good kernel	?	Yes	?	?	?	Yes	Yes
find filename on partition	?	?	?	?	?	?	Yes
filesystem test mode	?	?	?	?	Yes	Yes	Yes
help	?	Yes	?	?	Yes	Yes	Yes
display disk geometry	?	?	?	?	?	?	Yes
manually load config. file	?	Yes	?	?	?	?	?
halt machine	?	Yes	?	Yes	Yes	?	Yes
hide partition	?	?	?	?	Yes	?	Yes
file hexdump	?	Yes	?	?	?	?	?
intel multiprocessor probe	?	?	?	?	?	?	Yes
disk I/O port probe	?	?	?	?	?	?	Yes
load/save env. variables	?	Yes	?	?	Yes	Yes	?
show directory contents	?	Yes	?	?	Yes	Yes	?
probe PCI bus	?	Yes	?	?	?	?	?
set partition boot flag	?	?	?	?	?	?	Yes
map one drive to another	?	?	?	?	?	?	Yes
screen pager	?	?	?	?	?	?	Yes
partition manipulation	?	?	?	?	?	?	Yes
pause/sleep	?	Yes	?	?	?	?	Yes
read variables from user input	?	Yes	?	?	?	?	?
read memory address	?	?	?	?	?	?	Yes
reboot computer	?	Yes	?	Yes	Yes	?	?
select terminal	?	Yes	?	?	?	?	?
serial console support	?	?	?	?	?	?	Yes
set keyboard mappings	?	?	?	?	?	?	Yes
expression handling	?	Yes	?	?	?	?	?
video testing	?	Yes	?	?	?	?	?
list vbe modes	?	Yes	?	?	?	?	Yes
vbe test	?	Yes	?	?	?	?	?
load font files	?	Yes	?	?	?	?	?
block users from using EFI shell	?	?	?	Yes	Yes	?	?
disable booting from optical drive	?	?	?	Yes	Yes	?	?
disable booting from internal drives	?	?	?	Yes	Yes	?	?
block apple HW testing	?	?	?	Yes	Yes	?	?
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	Yes	?	?	?	Yes	?	?
DCHP	Yes	?	?	?	?	?	Yes
TFTP	Yes	?	?	?	?	?	Yes
BOOTP	?	?	?	?	?	?	Yes
IFCONFIG	?	?	?	?	?	?	Yes
RARP	?	?	?	?	?	?	Yes

Footnotes:

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)
Floating Point Software Assist (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) (3)

Booting from EFI

All EFI compliant systems have an EFI System Partition (ESP), which is a volume formatted with either a FAT16 or FAT32 filesystem containing EFI firmware modules and boot images. Note that there can be multiple EFI system partitions present on a system, with their order of precedence configured in the firmware setup menu. The ESP is effectively the boot partition, and contains the necessary images to boot a system. This boot partition should be mounted on a Linux system as /efi (formerly /boot/efi) for the updating of new kernels and initrd images.

Each vendor "must" use a dedicated directory within the \EFI\ directory (i.e. \EFI\vendor) for its EFI executable and other related files.

Shell.efi is the name of the UEFI Shell binary generated by the TianoCore EFI Development Kit (EDK) II. If present, it will execute a boot script with the filename startup.nsh in the root directory of an ESP. startup.nsh can be used to load and execute the preferred boot loader, or perform other tasks related to the ESP contents. More commonly, a list of boot loaders is maintained in NVRAM variables with names of the format Boot####, where #### is a hexadecimal value in a series beginning with 0000. The boot order is stored in the BootOrder variable and determines the order in which the system will attempt to execute the boot loaders that are configured. 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 fallback to using the boot loader located at \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.

External Links

Implementations
- The rEFInd Boot Manager
- GNU GRUB
- ELILO: EFI Linux Boot Loader
- rEFIt: An EFI Boot Menu and Toolkit
Documentation
- UEFI Specifications
- Intel UEFI resources (September 6, 2019)
- UEFI Shell Specification (v2.2 - January 26, 2016, a UEFI scripting primer)
- The Extensible Firmware Interface (September 1, 2005) and EFI Architecture (May 10, 2007) from Dr. Dobb's Journal
- Mac OS X Internals: More Power To Firmware by Amit Singh (June 2004, archived by The Wayback Machine on January 3, 2020)

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

-  ⇤ ← Revision 4 as of 2013-09-23 18:07:37 → 
  Size: 12012
  Editor: ip98-182-36-23
  Comment: Updated EFI filesystem driver information
+   ← Revision 9 as of 2023-12-07 18:11:36 → ⇥
  Size: 27843
  Editor: roguescholar
  Comment: Update links in References section
-Deletions are marked like this.
+Additions are marked like this.
 Line 4:
-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 and rEFInd can load a kernel only if it includes an EFI stub loader.)

Key:
Y - feature known to exist,
? - cannot determine,
blank - feature does not exist

||||||||<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>'''Features'''                ||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 ||   ||   ||   ||   ||
|| 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 (Jaunty+) ||
|| FFS                          ||   ||   ||   ||   ||   || 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 ||
+||<tablestyle="border-style: ridge; border-width: 3px; clear: both; float: right; margin-bottom: 2rem; margin-right: 4rem; text-align: center;" -2> '''Legend''' ||
||<style="background-color: #99ff99; text-align: center; width: 3.5rem;"> Yes || Feature known to exist ||
||<:#ececec>  ?  || Indeterminate feature presence ||
||<:#ff9999> No  || Feature does not exist ||

UEFI defines a new method of interfacing between PC operating systems and firmware. The UEFI interface is composed of data tables containing 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.)

<<BR>>

=== Comparison table ===
||<tablestyle="clear: both; margin: auto; width: 90%;"|3> '''Features''' ||<:-3> '''EFI/UEFI Bootloaders''' ||<:-3> '''EFI/UEFI Boot Managers''' ||<:14%> '''BIOS Bootloader''' ||
||<:14%> '''[[https://elilo.sourceforge.io/|ELILO|target="_blank"]]''' ||<:14%> '''[[https://www.gnu.org/software/grub/|GRUB 2|target="_blank"]]''' ||<:14%> '''[[https://www.kernel.org/doc/Documentation/efi-stub.txt|Kernel stub loader|target="_blank"]]''' ||<:14%> '''[[http://refit.sourceforge.net|rEFIt|target="_blank"]]''' ||<:14%> '''[[https://www.rodsbooks.com/refind/index.html|rEFInd|target="_blank"]]''' ||<:14%> '''[[https://systemd.io/BOOT_LOADER_SPECIFICATION/|systemd-boot|target="_blank"]]''' ||<:> '''[[https://www.gnu.org/software/grub/grub-legacy.html|GRUB 0.97|target="_blank"]]''' ||
||<:> 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; 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 ||
||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                     ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ff9999> No  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No  ||<:#99ff99> '''BIOS ONLY''' ||
||Chain loading	                         ||<:#ff9999> No  ||<:#99ff99> Yes ||<:#ff9999> No  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||Gzip compression support               ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||Load ELF binaries                      ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||Apple fat image                        ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||Boot unmodified linux kernel           ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||Relocate Kernel                        ||<:#ff9999> No  ||<:#99ff99> Yes ||<:#ff9999> No  ||<:#ff9999> No  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||IA-64 modified kernel                  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||Load FPSWA driver<<FootNote(Floating Point Software Assist)>> ||<:#99ff99> Yes (IA-64 only) ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ffefd5> N/A ||
||Custom font support                    ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No  ||<:#ececec>  ?  ||
||<rowstyle="background: #e9ba25; text-align: center; font-weight: 700;" -8> '''Architecture Support:'''                                                  ||
||x86-64                                 ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||x86-32                                 ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||IA-64                                  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||<rowstyle="background: #e9ba25; text-align: center; font-weight: 700;" -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))>> ||
|| Amiga FFS                             ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| AFS                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| Btrfs                                 ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| CPIO                                  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| EXT2                                  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
|| EXT3                                  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
|| EXT4                                  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes (Jaunty+) ||
|| FAT                                   ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
|| FFS                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ff9999> No  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| HFS                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| HFS+                                  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| ISO9660                               ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| JFS                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| MINIX                                 ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| NTFS                                  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| NTFS Compressed                       ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| ReiserFS                              ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
|| SFS (Amiga)                           ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| UDF                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| UFS                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| XFS                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| ZFS                                   ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||<rowstyle="background: #e9ba25; text-align: center; font-weight: 700;" -8> '''Disk Volume/Partition Support:'''                                         ||
|| RAID                                  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| LVM                                   ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| ADFS (Acorn partition maps)           ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| Amiga partition tables                ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| Macintosh partition tables            ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| Master Boot Record (MBR) tables       ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
|| Sun partition tables                  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| GPT (GUID partition tables)           ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ff9999> No  ||
|| Disk loopback                         ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
|| Filesystems by UUID/Label             ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes (Intrepid+) ||
||<rowstyle="background: #e9ba25; text-align: center; font-weight: 700;" -8> '''Image File Format Support:'''                                             ||
||  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>  ?  ||
||<rowstyle="background: #e9ba25; text-align: center; font-weight: 700;" -8> '''Command Line Operations'''                                                ||
||  background                           ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  beep (PC speaker)                    ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  print file block list                ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  set border color                     ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  read text file contents              ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  clear screen                         ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  compare files                        ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  identify CPU                         ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  debug mode                           ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  display APM BIOS info                ||<:#ffefd5> N/A ||<:#ffefd5> N/A ||<:#ececec>  ?  ||<:#ffefd5> N/A ||<:#ffefd5> N/A ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  display RAM info                     ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  dump file (copy)                     ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  echo / print                         ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  fallback to known good kernel        ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||  find filename on partition           ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  filesystem test mode                 ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||  help                                 ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#99ff99> Yes ||
||  display disk geometry                ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  manually load config. file           ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  halt machine                         ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  hide partition                       ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  file hexdump                         ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  intel multiprocessor probe           ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  disk I/O port probe                  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  load/save env. variables             ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||
||  show directory contents              ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||
||  probe PCI bus                        ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  set partition boot flag              ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  map one drive to another             ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  screen pager                         ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  partition manipulation               ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  pause/sleep                          ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  read variables from user input       ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  read memory address                  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  reboot computer                      ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  select terminal                      ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  serial console support               ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  set keyboard mappings                ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  expression handling	                 ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  video testing                        ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  list vbe modes                       ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  vbe test                             ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  load font files                      ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  block users from using EFI shell     ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  disable booting from optical drive   ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  disable booting from internal drives ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  block apple HW testing	         ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||<rowstyle="background: #e9ba25; text-align: center; font-weight: 700;" -8> '''Toolchain Contraints'''                                                   ||
||IA-64: gcc version                     ||<:> 3.1, 3.2   ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||IA-64: binutils                        ||<:> 2.13.90    ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||x86-32: gcc-version                    ||<:> 3.2        ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||x86-32: binutils                       ||<:> 2.13.90.0.2||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||x86-64: gcc-version                    ||<:> 4.1.1+     ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||x86-64: bintil                         ||<:> 2.17.50.0.14+||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||<rowstyle="background: #e9ba25; text-align: center; font-weight: 700;" -8> '''Netboot Methods:'''                                                       ||
||  PXE                                  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||
||  DCHP                                 ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  TFTP                                 ||<:#99ff99> Yes ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  BOOTP                                ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  IFCONFIG                             ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||
||  RARP                                 ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#ececec>  ?  ||<:#99ff99> Yes ||

<<BR>> '''Footnotes:''' <<BR>>
<<FootNote>>
-Line 142:
+Line 151:
-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.
+All EFI compliant systems have an EFI System Partition (ESP), which is a volume formatted with either a FAT16 or FAT32 filesystem containing EFI firmware modules and boot images. Note that there can be multiple EFI system partitions present on a system, with their order of precedence configured in the firmware setup menu. The ESP is effectively the boot partition, and contains the necessary images to boot a system. This boot partition should be mounted on a Linux system as `/efi` (formerly `/boot/efi`) for the updating of new kernels and initrd images.

Each vendor "must" use a dedicated directory within the `\EFI\` directory (i.e. `\EFI\vendor`) for its EFI executable and other related files.

[[https://github.com/tianocore/tianocore.github.io/wiki/ShellPkg|Shell.efi]] is the name of the UEFI Shell binary generated by the [[https://www.tianocore.org/|TianoCore EFI Development Kit (EDK) II]]. If present, it will execute a boot script with the filename `startup.nsh` in the root directory of an ESP. `startup.nsh` can be used to load and execute the preferred boot loader, or perform other tasks related to the ESP contents. More commonly, a list of boot loaders is maintained in NVRAM variables with names of the format `Boot####`, where #### is a hexadecimal value in a series beginning with 0000. The boot order is stored in the !BootOrder variable and determines the order in which the system will attempt to execute the boot loaders that are configured. 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 fallback to using the boot loader located at `\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.
-Line 161:
+Line 169:
-Line 165:
+Line 172:
-    CONFIG_FB_EFI=y
    CONFIG_FRAMEBUFFER_CONSOLE=y
+  CONFIG_FB_EFI=y
  CONFIG_FRAMEBUFFER_CONSOLE=y
-Line 171:
+Line 178:
-    CONFIG_EFI=y
    CONFIG_EFI_VARS=y or m          # optional
+  CONFIG_EFI=y
  CONFIG_EFI_VARS=y or m          # optional
-Line 177:
+Line 184:
-    CONFIG_EFI_STUB=y
+  CONFIG_EFI_STUB=y
-Line 182:
+Line 189:
-== References ==

 * UEFI specification: http://www.uefi.org
 * Intel EFI resources http://www.intel.com/technology/efi/
 * EFI scripting language http://software.intel.com/en-us/articles/efi-shells-and-scripting/
 * DDJ EFI background http://www.ddj.com/embedded/18440624 and http://www.ddj.com/embedded/199500688
 * EFI background in OSX book http://osxbook.com/book/bonus/chapter4/firmware/
 * ELILO: http://elilo.sourceforge.net/cgi-bin/blosxom
 * GRUB: http://www.gnu.org/software/grub/
 * rEFIt: http://refit.sourceforge.net
 * rEFInd: http://www.rodsbooks.com/refind/
+== External Links ==
 * '''~+Implementations+~'''
  * '''[[https://www.rodsbooks.com/refind/|The rEFInd Boot Manager]]'''
  * '''[[https://www.gnu.org/software/grub/index.html|GNU GRUB]]'''
  * '''[[https://elilo.sourceforge.io/|ELILO: EFI Linux Boot Loader]]'''
  * '''[[https://refit.sourceforge.net/|rEFIt: An EFI Boot Menu and Toolkit]]'''
 * '''~+Documentation+~'''
  * '''[[https://uefi.org/specifications|UEFI Specifications]]'''
  * '''[[https://www.intel.com/content/www/us/en/developer/articles/tool/unified-extensible-firmware-interface.html|Intel UEFI resources]]''' (September 6, 2019)
  * '''[[https://uefi.org/sites/default/files/resources/UEFI_Shell_2_2.pdf|UEFI Shell Specification]]''' (v2.2 - January 26, 2016, a UEFI scripting primer)
  * '''[[https://www.drdobbs.com/the-extensible-firmware-interface/184406244|The Extensible Firmware Interface]]''' (September 1, 2005) and '''[[https://www.drdobbs.com/embedded-systems/efi-architecture/199500688|EFI Architecture]]''' (May 10, 2007) from Dr. Dobb's Journal
  * '''[[https://web.archive.org/web/20200103161736if_/http://osxbook.com/book/bonus/chapter4/firmware/|Mac OS X Internals: More Power To Firmware]]''' by Amit Singh (June 2004, archived by The Wayback Machine on January 3, 2020)

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