20:
302:
executable image and appearing to the firmware as a UEFI application, a Linux kernel image with EFI Boot Stub enabled can be directly loaded and executed by a UEFI firmware. Such kernel images can still be loaded and run by BIOS-based boot loaders; thus, EFI Boot Stub allows a single kernel image to
570:
The file system supported by the
Extensible Firmware Interface is based on the FAT file system. EFI defines a specific version of FAT that is explicitly documented and testable. Conformance to the EFI specification and its associate reference documents is the only definition of FAT that needs to be
180:
The UEFI specification requires MBR partition tables to be fully supported. However, some UEFI implementations immediately switch to the BIOS-based CSM booting upon detecting certain types of partition table on the boot disk, effectively preventing UEFI booting from being performed from EFI system
123:
and maintained as part of the UEFI specification; therefore, the file system specification is independent from the original FAT specification. The actual extent of divergence is unknown: Apple maintains a separate tool that should be used on Intel/x86-64 Macs, while other systems use FAT utilities
200:
file system, while a boot loader needs to be stored according to the standard ESP file hierarchy, or by providing a complete path of a boot loader to the system's boot manager. On the other hand, FAT32 is always expected on fixed drives.
173:-based systems, the first sector of a partition is loaded into memory, and execution is transferred to this code. UEFI firmware does not execute the code in the MBR, except when booting in legacy BIOS mode through the
239:
managers) for Linux. Once loaded by a UEFI firmware, they can access and boot kernel images from all devices, partitions and file systems they support, without being limited to the EFI system partition.
324:
images are required to reside on the EFI system partition, as systemd-boot does not provide support for accessing files on other partitions or file systems. Linux kernels need to be built with
320:
is a simple UEFI boot manager that loads and runs configured EFI images, accessing only the EFI system partition. Configuration file fragments, kernel images and
445:) such as iPhones, iPads and all Mac computers from 2023 onward do not contain EFI/UEFI functionality and subsequently do not use EFI system partitions.
736:
583:
1039:
994:
146:. Both GPT- and MBR-partitioned disks can contain an EFI system partition, as UEFI firmware is required to support both partitioning schemes. Also,
932:
1158:
395:
97:
at boot time, system utility programs that are intended to be run before an operating system is booted, and data files such as error logs.
174:
795:
106:
110:
215:
571:
implemented to support EFI. To differentiate the EFI file system from pure FAT, a new partition file system type has been defined.
165:
with legacy systems by reserving the first block (sector) of the partition for compatibility code, effectively creating a legacy
421:. There are otherwise no limitations to what kinds of EFI operating system or bootloader an Intel-based Apple computer can run.
715:
63:
908:
490:
414:
760:
1148:
551:
471:
command. Mounts the EFI system partition on the specified drive. Available on
Itanium-based computers only.
1047:
402:
1015:
839:
683:
147:
884:
125:
360:
processor architecture, the EFI system partition is initially left blank and unused for booting into
940:
1153:
986:
817:"rEFIt: Myths and Facts About Intel Macs – Myth: Mac OS X Requires a Hidden EFI System Partition"
386:
will select the desired bootloader (potentially configured via
Startup Keyboard Combinations or
247:
for the EFI system partition varies depending on the bootloader used. Older bootloaders such as
279:
mounts. Regardless of the mount point path, its contents are accessible after Linux is booted.
162:
785:
367:
However, the EFI system partition is used as a staging area for firmware updates and for the
311:
47:
24:
608:
1095:
372:
310:(EFI stub support) during the kernel configuration. It was merged into version 3.3 of the
129:
19:
8:
480:
295:
51:
467:
64-Bit
Edition and later, access to the EFI system partition is obtained by running the
962:
142:
137:
524:"Unified Extensible Firmware Interface (UEFI) Specification (versions 2.10 and older)"
368:
252:
59:
707:
633:
89:
of installed operating systems (which are typically contained in other partitions),
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71:
790:
391:
185:
120:
55:
418:
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bootloader for Mac computers configured to boot into a
Windows partition using
294:
image without the use of a conventional UEFI boot loader. By masquerading as a
1137:
495:
438:
426:
306:
Linux kernel's support for the EFI Boot Stub is enabled by turning on option
90:
485:
390:), optionally falling back to either the internal macOS Installation, or a
317:
291:
260:
232:
228:
86:
82:
658:
244:
166:
116:
78:
864:"Firmware updates for Intel-based Macs require a GUID partition scheme"
464:
236:
816:
523:
184:
UEFI firmware supports booting from removable storage devices such as
1070:"Subdirectory Registry | Unified Extensible Firmware Interface Forum"
863:
737:"Linux kernel 3.11.1 arch/x86/Kconfig: CONFIG_EFI_STUB (line #1575)"
248:
94:
909:"Startup Security Utility on a Mac with an Apple T2 Security Chip"
885:"Boot modes of an Intel-based Mac with an Apple T2 Security Chip"
552:"UEFI Specification Version 2.5, Section 12.3 File System Format"
442:
430:
413:
command before becoming bootable by the firmware, a relic of the
93:
files for hardware devices present in a computer and used by the
67:
424:
453:
UEFI support in
Windows began in 2008 with Windows Vista® SP1.
357:
346:
321:
220:
151:
634:"UEFI system booting from MBR partition table and GRUB legacy"
409:. Third-party bootloaders needed to be "blessed" by a special
405:
machines required the EFI system partition to be formatted in
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383:
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224:
197:
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188:. For that purpose, a removable device is formatted with a
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155:
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controls the logic for finding and loading bootloaders.
70:, UEFI firmware loads files stored on the ESP to start
16:
Partition used by
Unified Extensible Firmware Interface
1126:– A registry of the subdirectories that lie below the
1046:. Microsoft Corporation. July 24, 2008. Archived from
708:"The EFI Boot Stub - The Linux Kernel Documentation"
231:
serve as conventional, full-fledged standalone UEFI
336:
328:so they can be directly executed as UEFI images.
1135:
181:partitions contained on MBR-partitioned disks.
23:Example of an EFI system partition as shown by
1100:Windows Server 2012 R2 and Windows Server 2012
282:
115:The EFI system partition is formatted with a
544:
518:
516:
514:
512:
510:
1016:"Boot process for a Mac with Apple silicon"
584:"Technical Note TN2166: Secrets of the GPT"
456:The Windows boot manager is located at the
275:due to potential complications with nested
128:(GUID) for the EFI system partition in the
1124:EFI System Partition Subdirectory Registry
761:"Linux kernel 3.3: 1.10. EFI boot support"
62:) that is used by computers that have the
1044:Windows Hardware Developer Central (WHDC)
507:
987:"Introduction to Apple Silicon: Storage"
216:UEFI and Linux disk device compatibility
18:
659:"UEFI - Community Ubuntu Documentation"
460:subfolder of the EFI system partition.
1136:
1159:Unified Extensible Firmware Interface
1102:. learn.microsoft.com. 31 August 2016
879:
877:
840:"Boot process for an Intel-based Mac"
834:
832:
830:
64:Unified Extensible Firmware Interface
1130:directory on an EFI system partition
134:C12A7328-F81F-11D2-BA4B-00A0C93EC93B
119:whose specification is based on the
491:System partition and boot partition
13:
939:. 7 September 2014. Archived from
937:The Slightly Disgruntled Scientist
874:
827:
14:
1170:
1117:
378:Custom Apple UEFI firmware named
786:"systemd-boot UEFI Boot Manager"
140:(MBR) partition-table scheme is
1088:
1062:
1032:
1008:
997:from the original on 2024-02-14
979:
955:
925:
901:
856:
809:
798:from the original on 2024-02-14
778:
753:
718:from the original on 2023-10-04
561:. April 2015. pp. 536, 537
457:
729:
712:The Linux Kernel documentation
700:
676:
651:
626:
601:
576:
314:, released on March 18, 2012.
303:work in any boot environment.
1:
933:"Ubuntu + Mac: Pure EFI Boot"
501:
353:On Apple Mac computers using
36:Extensible Firmware Interface
290:makes it possible to boot a
175:Compatibility Support Module
7:
684:"Boot Loader Specification"
474:
100:
66:(UEFI). When a computer is
10:
1175:
448:
283:Linux Kernel EFI Boot Stub
213:
126:globally unique identifier
104:
991:GitHub - Asahi Linux Wiki
403:Apple–Intel architecture
331:
209:
204:
74:and various utilities.
609:"EFI system partition"
425:iOS, iPadOS, macOS on
415:System Folder blessing
163:backward compatibility
136:, while its ID in the
27:
1149:Computer file systems
821:rEFIt.SourceForge.net
312:Linux kernel mainline
25:KDE Partition Manager
22:
458:\EFI\Microsoft\Boot\
150:bootable format for
130:GUID Partition Table
77:An ESP contains the
868:Apple Knowledgebase
588:Developer.Apple.com
481:BIOS boot partition
107:UEFI § UEFI booting
52:data storage device
1050:on January 4, 2009
1040:"UEFI and Windows"
138:master boot record
111:UEFI § CSM booting
28:
765:KernelNewbies.org
369:Microsoft Windows
326:CONFIG_EFI_STUB=y
259:. Alternatively,
72:operating systems
60:solid-state drive
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186:USB flash drives
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132:(GPT) scheme is
40:system partition
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1154:Disk partitions
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967:keith.github.io
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943:on 8 March 2021
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791:Freedesktop.org
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401:Older pre-UEFI
392:recovery system
351:
334:
325:
308:CONFIG_EFI_STUB
307:
285:
276:
272:
268:
264:
263:prefers either
256:
218:
212:
207:
141:
133:
124:just fine. The
121:FAT file system
113:
103:
56:hard disk drive
17:
12:
11:
5:
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1118:External links
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1007:
993:. 2023-11-02.
978:
954:
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794:. 2021-05-07.
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714:. 2014-06-16.
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688:uapi-group.org
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437:Devices using
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419:Classic Mac OS
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284:
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211:
208:
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161:UEFI provides
158:is supported.
102:
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1020:Apple Support
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996:
992:
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913:Apple Support
910:
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889:Apple Support
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844:Apple Support
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639:
638:ArchLinux.org
635:
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579:
572:
560:
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547:
533:. August 2022
532:
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519:
517:
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511:
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497:
496:Windows To Go
494:
492:
489:
487:
484:
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479:
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472:
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461:
454:
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444:
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439:Apple silicon
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427:Apple silicon
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289:
288:EFI Boot Stub
280:
262:
254:
250:
246:
241:
238:
234:
233:boot managers
230:
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127:
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118:
112:
108:
98:
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92:
91:device driver
88:
87:kernel images
84:
83:boot managers
80:
75:
73:
69:
65:
61:
57:
53:
49:
45:
41:
37:
33:
26:
21:
1104:. Retrieved
1099:
1090:
1078:. Retrieved
1076:. UEFI Forum
1073:
1064:
1052:. Retrieved
1048:the original
1043:
1034:
1023:. Retrieved
1019:
1010:
999:. Retrieved
990:
981:
970:. Retrieved
966:
957:
945:. Retrieved
941:the original
936:
927:
916:. Retrieved
912:
903:
892:. Retrieved
888:
867:
858:
847:. Retrieved
843:
820:
811:
800:. Retrieved
789:
780:
769:. Retrieved
767:. 2012-03-18
764:
755:
744:. Retrieved
740:
731:
720:. Retrieved
711:
702:
691:. Retrieved
687:
678:
667:. Retrieved
665:. 2013-12-21
662:
653:
642:. Retrieved
637:
628:
616:. Retrieved
612:
603:
592:. Retrieved
590:. 2006-11-06
587:
578:
569:
563:. Retrieved
558:
546:
535:. Retrieved
530:
486:EFI variable
462:
455:
452:
436:
400:
377:
366:
352:
318:Systemd-boot
316:
305:
292:Linux kernel
287:
286:
261:systemd-boot
242:
229:systemd-boot
219:
183:
179:
169:. On legacy
160:
114:
79:boot loaders
76:
43:
39:
35:
31:
29:
947:17 November
640:. June 2012
255:default to
245:mount point
167:boot sector
117:file system
54:(usually a
1138:Categories
1096:"Mountvol"
1025:2024-02-14
1001:2024-02-14
972:2024-02-14
963:"BLESS(8)"
918:2024-02-14
894:2024-02-14
849:2024-02-14
802:2024-02-14
771:2013-10-06
746:2013-10-06
741:Kernel.org
722:2024-02-14
693:2024-02-15
669:2013-12-27
663:Ubuntu.com
644:2013-10-06
594:2015-05-06
565:2015-05-29
537:2022-12-12
502:References
465:Windows XP
396:recoveryOS
253:lilo/elilo
237:bootloader
214:See also:
105:See also:
373:Boot Camp
337:macOS on
273:/boot/efi
257:/boot/efi
148:El Torito
48:partition
1074:uefi.org
995:Archived
796:Archived
716:Archived
618:14 March
613:ArchWiki
559:UEFI.org
531:UEFI.org
475:See also
469:mountvol
235:(a.k.a.
101:Overview
95:firmware
1144:Booting
449:Windows
443:AArch64
431:AArch64
394:called
177:(CSM).
152:CD-ROMs
1054:May 5,
358:x86-64
347:x86-64
322:initrd
277:autofs
249:GRUB 2
221:GRUB 2
109:, and
68:booted
1106:5 May
1080:5 May
555:(PDF)
527:(PDF)
417:from
411:ioctl
388:NVRAM
384:iBoot
380:iBoot
362:macOS
355:Intel
339:Intel
332:Apple
271:over
269:/boot
225:elilo
210:Linux
205:Usage
198:FAT32
194:FAT16
190:FAT12
85:, or
50:on a
46:is a
1128:/EFI
1108:2024
1082:2024
1056:2024
949:2019
620:2020
407:HFS+
345:and
300:COFF
265:/efi
251:and
243:The
227:and
171:BIOS
156:DVDs
154:and
143:0xEF
30:The
463:On
343:x86
267:or
196:or
58:or
44:ESP
42:or
32:EFI
1140::
1098:.
1072:.
1042:.
1018:.
989:.
965:.
935:.
911:.
887:.
876:^
866:.
842:.
829:^
819:.
788:.
763:.
739:.
710:.
686:.
661:.
636:.
611:.
586:.
568:.
557:.
529:.
509:^
398:.
375:.
364:.
296:PE
223:,
192:,
81:,
38:)
1110:.
1084:.
1058:.
1028:.
1004:.
975:.
951:.
921:.
897:.
870:.
852:.
823:.
805:.
774:.
749:.
725:.
696:.
672:.
647:.
622:.
597:.
540:.
441:(
433:)
429:(
349:)
341:(
298:/
34:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
