Bootmgr

Bootmgr

Print second-stage bootloader information (name, firmware, etc.)

Module type	bootmgr
Default order	6 (only used by --gen-config)
Module source	src/modules/bootmgr/bootmgr.c
Detection source	src/detection/bootmgr/

Prints the currently selected boot entry and the firmware file it loads.

Boot Manager: Windows Boot Manager - \EFI\Microsoft\Boot\bootmgfw.efi

Note the naming: the module's type is bootmgr and its .name — which is what the JSON type field reports — is Bootmgr, but the printed key is the display name Boot Manager. "Bootmgr" in a config is accepted; "Boot Manager" is not.

Platform support

Platform	Implementation	Notes
Linux	bootmgr_linux.c	UEFI variables in /sys/firmware/efi/efivars/
macOS	bootmgr_apple.c	IOKit device tree
Windows	bootmgr_windows.c	NtQuerySystemEnvironmentValueEx + SeSystemEnvironmentPrivilege
Haiku	bootmgr_haiku.cpp	Hard-coded Haiku loader path
FreeBSD / NetBSD / OpenBSD	bootmgr_bsd.c	kenv/efi properties
Android / Solaris / GNU/Hurd	bootmgr_nosupport.c	Reports Not supported on this platform

Configuration

Key	Type	Default	Description
key	string	module name	Module key. A single space hides the key and the separator.
keyColor	color	–	Overrides display.color.keys.
keyWidth	integer	–	Overrides display.key.width.
keyIcon	string	built-in glyph	Printed when display.key.type includes the icon bit. Any glyph works; "" prints none.
outputColor	color	–	Overrides display.color.output.
format	string	–	Custom output format (see below).
condition	object	–	Show the module only if the conditions match.

There are no module-specific keys.

Format string

Run fastfetch -h bootmgr-format for the authoritative list.

Variable	Description
{name}	Name / description of the boot entry
{firmware-path}	Full path of the firmware file
{firmware-name}	File name part of the firmware path
{secure-boot}	true / false
{order}	Boot order index of the selected entry

JSON output

{
    "type": "Bootmgr",
    "result": {
        "name": "Windows Boot Manager",
        "firmware": "\\EFI\\Microsoft\\Boot\\bootmgfw.efi",
        "order": 1,
        "secureBoot": true
    }
}

Examples

{ "type": "bootmgr", "format": "{name}" }

{ "type": "bootmgr", "key": "Boot", "format": "{name} ({firmware-name}) secure={secure-boot}" }

Pitfalls

• {secure-boot} cannot distinguish "disabled" from "unknown". The result field starts as false and is only overwritten when the platform can actually read the setting. On Linux that means the SecureBoot EFI variable was readable, and on macOS that an IOKit property existed; when either probe fails the module silently prints false.
• Nothing is printed on a legacy-boot machine. The Linux reader needs /sys/firmware/efi/efivars/BootCurrent-<GUID>; without it the module reports Failed to read efivar: BootCurrent rather than falling back to the MBR/BIOS bootloader.
• Windows needs administrator rights. The reader enables SeSystemEnvironmentPrivilege, and when the token lacks it the error is literally The token does not have the specified privilege; try sudo please.
• macOS usually reports an empty {firmware-path}. The path is only filled in when /System/Library/CoreServices/boot.efi exists, which is not the case on Apple Silicon, so - (with nothing after the dash) is not printed and {firmware-name} is empty.
• {firmware-name} only understands UEFI paths. For every platform except Apple it splits on the last \, matching the UEFI File Path Media Device Path convention. Haiku hard-codes a /-separated path (/system/haiku_loader.bios_ia32), so on Haiku {firmware-name} returns the whole path.
• {order} is a boot entry number, not a list. It is the #### of BootCurrent, i.e. the index of the entry that was booted — not the firmware's boot order.
• The macOS name is truncated at the first -. mBoot-9.9.9 becomes mBoot.

Implementation

Linux

Reads /sys/firmware/efi/efivars/BootCurrent-<EFI_GLOBAL_GUID> into a 2048-byte aligned buffer and expects exactly 6 bytes; the firmware-reported value is the 16-bit little-endian uint16_t at offset 4 (the first four bytes are the EFI variable attributes). That number is formatted as Boot%04X and read back, together with the SecureBoot variable, whose byte 4 is 1 when secure boot is enabled.

The Boot#### payload is decoded by the shared ffEfiFillLoadOption(): the variable's first four bytes are skipped, then the structure is read as FFEfiLoadOption (Attributes, FilePathListLength, a UCS-2 Description[]). The description is converted to UTF-8 by hand, and the device-path list is walked node by node using each node's own Length until the end-of-list type 0x7F; the first File Path Media Device Path (type 4, subtype 4) is decoded into {firmware-path}. A payload that is not at least 5 + sizeof(FFEfiLoadOption) bytes long, or that exactly fills the 2048-byte buffer, is rejected as Failed to read efivar: Boot#### — the second condition is how the code detects that the variable was longer than the buffer.

Windows

enablePrivilege(L"SeSystemEnvironmentPrivilege") is called first, through NtOpenProcessToken / NtAdjustPrivilegesToken. A STATUS_NOT_ALL_ASSIGNED result is reported as a privileges error rather than as a generic failure.

The firmware variables are then read with NtQuerySystemEnvironmentValueEx, using RtlGUIDFromString on {8be4df61-…}. Both calls validate the returned size: BootCurrent must return exactly sizeof(uint16_t), and Boot#### must neither be shorter than sizeof(FFEfiLoadOption) nor fill the 2048-byte buffer exactly. The payload is decoded by the same ffEfiFillLoadOption() as on Linux, so the two platforms agree on how a UEFI boot entry is parsed. Secure boot comes from SystemSecureBootInformation, which is a direct query rather than an EFI variable, so it does not depend on the privilege above.

macOS

The reader is deliberately minimal: /System/Library/CoreServices/boot.efi is recorded as {firmware-path} when the file exists, and the bootloader name comes from IODeviceTree:/chosen's iboot-stage-two-tag, falling back to system-firmware-version. The name is cut at the first - and defaults to iBoot.

Secure boot is probed differently per architecture. On __aarch64__ the secure-boot property of IODeviceTree:/chosen is read as a single byte. On Intel the AppleSecureBootPolicy property of IODeviceTree:/options is read instead, and "secure" means any value other than 0x02 (Permissive Security). Both paths validate the property's Core Foundation type and length before dereferencing, and both return an error string that the caller discards only after assigning to the result — a probe failure leaves false.