efidebug command
Synopsis
efidebug boot add -b <bootid> <label> <interface> <devnum>[:<part>] <file>
efidebug boot rm <bootid> [<bootid> ...]
efidebug boot dump
efidebug boot next <bootid>
efidebug boot order [<bootid> ...]
efidebug log
efidebug media
efidebug memmap [-s]
Description
The efidebug command provides access some EFI features, including boot management, memory mapping, and system information.
efidebug boot
The boot subcommands manage UEFI boot options (BootXXXX variables) and boot order.
- efidebug boot add
Create or modify a UEFI boot option. The basic syntax is:
efidebug boot add -b <bootid> <label> <interface> <devnum>[:<part>] <file>Where:
<bootid>is a hexadecimal boot option ID (e.g., 0001, 000A)<label>is a descriptive name for the boot option<interface>is the storage interface (e.g., mmc, usb, virtio)<devnum>[:<part>]specifies device and optionally partition number<file>is the path to the EFI executable
Additional options include
-ifor initrd,-sfor optional data, and-dfor device tree files.- efidebug boot rm
Remove one or more UEFI boot options by their boot IDs.
- efidebug boot dump
List all defined UEFI boot options with their details including boot ID, label, and file path.
- efidebug boot next
Set the BootNext variable to specify which boot option should be used for the next boot only.
- efidebug boot order
Show the current boot order when called without arguments, or sets a new boot order when given a list of boot IDs.
efidebug log
This shows a log of EFI boot-services calls which have been handled since U-Boot started. This can be useful to see what the app is doing, or even what U-Boot itself has called.
efidebug media
This shows a list of all EFI media devices, their likely U-Boot uclass, and their corresponding device paths. Each EFI media device represents a block device that was discovered through EFI boot services, such as hard drives, USB storage, or other bootable media. The U-Boot Class column shows which U-Boot driver subsystem would likely handle the device (e.g., “ahci” for SATA drives, “usb” for USB storage). The device path shows the EFI device path for each device, which can be useful for debugging boot issues or understanding the system topology.
efidebug memmap
This shows the UEFI memory map, which displays all memory regions and their types as known to the EFI loader subsystem. This includes information about memory allocation, reserved regions, and available memory.
The command supports an optional ‘-s’ flag to sort the memory map entries by address, making it easier to visualize the memory layout in ascending order.
Example
This shows managing UEFI boot options:
=> efidebug boot add -b 1 "Ubuntu" mmc 0:2 /EFI/ubuntu/grubx64.efi
=> efidebug boot add -b 2 "Windows" mmc 0:1 /EFI/Microsoft/Boot/bootmgfw.efi
=> efidebug boot dump
Boot0001:
attributes: A-- (0x00000001)
label: Ubuntu
file_path: /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/SD(0)/
HD(2,GPT,dfae5a37-e8d5-4a2e-aab6-6b6e8c8cb8a3,0x100800,
0x5dc1800)/\EFI\ubuntu\grubx64.efi
data:
Boot0002:
attributes: A-- (0x00000001)
label: Windows
file_path: /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/SD(0)/
HD(1,GPT,c8a9e8e7-2d2a-4b8e-9b4f-7b7b3b7b7b7b,0x800,
0x100000)/\EFI\Microsoft\Boot\bootmgfw.efi
data:
=> efidebug boot order 1 2
=> efidebug boot order
BootOrder: 0001 0002
=> efidebug boot next 2
=> efidebug boot rm 1
This shows checking the EFI media devices:
=> efidebug media
Device Media type Device Path
------------------- --------------- -----------
efi_media_1 ahci PciRoot(0x0)/Pci(0x3,0x0)/
Sata(0x0,0xFFFF,0x0)
efi_media_2 pci PciRoot(0x0)/Pci(0x5,0x0)
This shows checking the UEFI memory map, first unsorted and then sorted by address:
=> efidebug mem
Type Start End Attributes
================ ================ ================ ==========
CONVENTIONAL 0000000040000000-0000000044000000 WB
BOOT DATA 0000000044000000-0000000044020000 WB
CONVENTIONAL 0000000044020000-00000000475ee000 WB
BOOT DATA 00000000475ee000-0000000047610000 WB
BOOT CODE 0000000047610000-0000000047647000 WB
BOOT DATA 0000000047647000-0000000047ef2000 WB
BOOT CODE 0000000047ef2000-0000000047ef6000 WB
BOOT DATA 0000000047ef6000-0000000047ff7000 WB
BOOT CODE 0000000047ff7000-0000000047ffa000 WB
BOOT DATA 0000000047ffa000-0000000048000000 WB
CONVENTIONAL 0000000048000000-00000000e0000000 WB
LOADER DATA 00000000e0000000-0000000100000000 WB
CONVENTIONAL 0000000100000000-000000013c278000 WB
LOADER DATA 000000013c278000-000000013c27c000 WB
LOADER CODE 000000013c27c000-000000013c3e0000 WB
ACPI RECLAIM MEM 000000013c3e0000-000000013c3f0000 WB
RUNTIME CODE 000000013c3f0000-000000013c470000 WB|RT
RUNTIME DATA 000000013c470000-000000013c630000 WB|RT
RUNTIME CODE 000000013c630000-000000013c730000 WB|RT
CONVENTIONAL 000000013c730000-000000013dc2a000 WB
BOOT DATA 000000013dc2a000-000000013e9f1000 WB
CONVENTIONAL 000000013e9f1000-000000013e9fe000 WB
BOOT DATA 000000013e9fe000-000000013ea1c000 WB
CONVENTIONAL 000000013ea1c000-000000013ea1e000 WB
BOOT DATA 000000013ea1e000-000000013ea47000 WB
CONVENTIONAL 000000013ea47000-000000013ea48000 WB
BOOT DATA 000000013ea48000-000000013f624000 WB
CONVENTIONAL 000000013f624000-000000013f731000 WB
BOOT CODE 000000013f731000-000000013fc00000 WB
RUNTIME CODE 000000013fc00000-000000013fd90000 WB|RT
RUNTIME DATA 000000013fd90000-000000013ffe0000 WB|RT
CONVENTIONAL 000000013ffe0000-000000013ffff000 WB
BOOT DATA 000000013ffff000-0000000140000000 WB
IO 0000000004000000-0000000008000000 UC|RT
IO 0000000009010000-0000000009011000 UC|RT
=> efidebug mem -s
Type Start End Attributes
================ ================ ================ ==========
IO 0000000004000000-0000000008000000 UC|RT
IO 0000000009010000-0000000009011000 UC|RT
CONVENTIONAL 0000000040000000-0000000044000000 WB
BOOT DATA 0000000044000000-0000000044020000 WB
CONVENTIONAL 0000000044020000-00000000475ee000 WB
BOOT DATA 00000000475ee000-0000000047610000 WB
BOOT CODE 0000000047610000-0000000047647000 WB
BOOT DATA 0000000047647000-0000000047ef2000 WB
BOOT CODE 0000000047ef2000-0000000047ef6000 WB
BOOT DATA 0000000047ef6000-0000000047ff7000 WB
BOOT CODE 0000000047ff7000-0000000047ffa000 WB
BOOT DATA 0000000047ffa000-0000000048000000 WB
CONVENTIONAL 0000000048000000-00000000e0000000 WB
LOADER DATA 00000000e0000000-0000000100000000 WB
CONVENTIONAL 0000000100000000-000000013c278000 WB
LOADER DATA 000000013c278000-000000013c27c000 WB
LOADER CODE 000000013c27c000-000000013c3e0000 WB
ACPI RECLAIM MEM 000000013c3e0000-000000013c3f0000 WB
RUNTIME CODE 000000013c3f0000-000000013c470000 WB|RT
RUNTIME DATA 000000013c470000-000000013c630000 WB|RT
RUNTIME CODE 000000013c630000-000000013c730000 WB|RT
CONVENTIONAL 000000013c730000-000000013dc2a000 WB
BOOT DATA 000000013dc2a000-000000013e9f1000 WB
CONVENTIONAL 000000013e9f1000-000000013e9fe000 WB
BOOT DATA 000000013e9fe000-000000013ea1c000 WB
CONVENTIONAL 000000013ea1c000-000000013ea1e000 WB
BOOT DATA 000000013ea1e000-000000013ea47000 WB
CONVENTIONAL 000000013ea47000-000000013ea48000 WB
BOOT DATA 000000013ea48000-000000013f624000 WB
CONVENTIONAL 000000013f624000-000000013f731000 WB
BOOT CODE 000000013f731000-000000013fc00000 WB
RUNTIME CODE 000000013fc00000-000000013fd90000 WB|RT
RUNTIME DATA 000000013fd90000-000000013ffe0000 WB|RT
CONVENTIONAL 000000013ffe0000-000000013ffff000 WB
BOOT DATA 000000013ffff000-0000000140000000 WB
=>
This shows checking the log, then using ‘efidebug tables’ to fully set up the EFI-loader subsystem, then checking the log again:
=> efidebug log
EFI log (size 158)
0 alloc_pool bt-data size 33/51 buf 7fffd8448ad0 *buf 7c20010 ret OK
1 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448a80 *mem 7c20000 ret OK
2 alloc_pool bt-data size 60/96 buf 7fffd8448ac0 *buf 7c1f010 ret OK
3 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448a60 *mem 7c1f000 ret OK
4 alloc_pool bt-data size 60/96 buf 7fffd8448ac0 *buf 7c1e010 ret OK
5 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448a60 *mem 7c1e000 ret OK
6 records
=> efidebug tables
efi_var_to_file() Cannot persist EFI variables without system partition
0000000017bfc010 36122546-f7ef-4c8f-bd9b-eb8525b50c0b EFI Conformance Profiles Table
0000000017bd4010 b122a263-3661-4f68-9929-78f8b0d62180 EFI System Resource Table
0000000017bd8010 1e2ed096-30e2-4254-bd89-863bbef82325 TCG2 Final Events Table
0000000017bd6010 eb66918a-7eef-402a-842e-931d21c38ae9 Runtime properties
0000000008c49000 8868e871-e4f1-11d3-bc22-0080c73c8881 ACPI table
0000000018c5b000 f2fd1544-9794-4a2c-992e-e5bbcf20e394 SMBIOS3 table
=> efidebug log
EFI log (size a20)
0 alloc_pool bt-data size 33/51 buf 7fffd8448ad0 *buf 7c20010 ret OK
1 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448a80 *mem 7c20000 ret OK
2 alloc_pool bt-data size 60/96 buf 7fffd8448ac0 *buf 7c1f010 ret OK
3 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448a60 *mem 7c1f000 ret OK
4 alloc_pool bt-data size 60/96 buf 7fffd8448ac0 *buf 7c1e010 ret OK
5 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448a60 *mem 7c1e000 ret OK
6 alloc_pages any-pages rt-data pgs 20/32 mem 7fffd8448838 *mem 7bfe000 ret OK
7 alloc_pool rt-data size 60/96 buf 7fffd84487e0 *buf 7bfd010 ret OK
8 alloc_pages any-pages rt-data pgs 1 mem 7fffd8448780 *mem 7bfd000 ret OK
9 alloc_pool rt-data size 180/384 buf 56f190ffd890 *buf 7bfc010 ret OK
10 alloc_pages any-pages rt-data pgs 1 mem 7fffd8448800 *mem 7bfc000 ret OK
11 alloc_pool bt-data size 4 buf 7fffd8448840 *buf 7bfb010 ret OK
12 alloc_pages any-pages bt-data pgs 1 mem 7fffd84487f0 *mem 7bfb000 ret OK
13 alloc_pool bt-data size 10/16 buf 7fffd8448728 *buf 7bfa010 ret OK
14 alloc_pages any-pages bt-data pgs 1 mem 7fffd84486d0 *mem 7bfa000 ret OK
15 alloc_pool bt-data size 60/96 buf 7fffd84487e0 *buf 7bf9010 ret OK
16 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448780 *mem 7bf9000 ret OK
17 alloc_pool bt-data size 10000/65536 buf 56f19100fae0 *buf 7be8010 ret OK
18 alloc_pages any-pages bt-data pgs 11/17 mem 7fffd84487d0 *mem 7be8000 ret OK
19 alloc_pool acpi-nvs size 10000/65536 buf 56f19100fae8 *buf 7bd7010 ret OK
20 alloc_pages any-pages acpi-nvs pgs 11/17 mem 7fffd84487d0 *mem 7bd7000 ret OK
21 alloc_pool bt-data size 60/96 buf 7fffd84487d0 *buf 7bd6010 ret OK
22 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448770 *mem 7bd6000 ret OK
23 alloc_pool rt-data size 8 buf 7fffd8448818 *buf 7bd5010 ret OK
24 alloc_pages any-pages rt-data pgs 1 mem 7fffd84487c0 *mem 7bd5000 ret OK
25 alloc_pool bt-data size 8 buf 7fffd8448360 *buf 7bd4010 ret OK
26 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448160 *mem 7bd4000 ret OK
27 alloc_pool bt-data size f0/240 buf 7fffd8448378 *buf 7bd3010 ret OK
28 alloc_pages any-pages bt-data pgs 1 mem 7fffd84482d0 *mem 7bd3000 ret OK
29 free_pool buf 7bd3010 ret OK
30 free_pages mem 7bd3000 pag 1 ret OK
31 alloc_pool bt-data size 60/96 buf 7fffd84482d8 *buf 7bd3010 ret OK
32 alloc_pages any-pages bt-data pgs 1 mem 7fffd8448280 *mem 7bd3000 ret OK
33 free_pool buf 7bfa010 ret OK
34 free_pages mem 7bfa000 pag 1 ret OK
35 alloc_pool bt-data size f0/240 buf 7fffd8448380 *buf 7bfa010 ret OK
36 alloc_pages any-pages bt-data pgs 1 mem 7fffd84482d0 *mem 7bfa000 ret OK
37 free_pool buf 7bfa010 ret OK
38 free_pages mem 7bfa000 pag 1 ret OK
39 free_pool buf 7bd4010 ret OK
40 free_pages mem 7bd4000 pag 1 ret OK
41 alloc_pool bt-data size 61/97 buf 7fffd8448810 *buf 7bfa010 ret OK
42 alloc_pages any-pages bt-data pgs 1 mem 7fffd84487c0 *mem 7bfa000 ret OK
43 alloc_pool bt-data size 60/96 buf 7fffd8448800 *buf 7bd4010 ret OK
44 alloc_pages any-pages bt-data pgs 1 mem 7fffd84487a0 *mem 7bd4000 ret OK
45 alloc_pool bt-data size 60/96 buf 7fffd8448800 *buf 7bd2010 ret OK
46 alloc_pages any-pages bt-data pgs 1 mem 7fffd84487a0 *mem 7bd2000 ret OK
47 alloc_pool bt-data size 60/96 buf 7fffd8448810 *buf 7bd1010 ret OK
48 alloc_pages any-pages bt-data pgs 1 mem 7fffd84487b0 *mem 7bd1000 ret OK
49 records
=>