efibootmgr-18

#### Beyond Linux® From Scratch (System V Edition) - Version r13.0-1374

### Chapter 5. File Systems and Disk Management

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# efibootmgr-18

## Introduction to efibootmgr

The efibootmgr package provides tools and libraries to manipulate EFI variables.

### Note

This version of BLFS may not build or run some packages properly if LFS or dependencies have been updated since the most recent stable version of the System V books.

### Package Information

- Download (HTTP): https://github.com/rhboot/efibootmgr/archive/18/efibootmgr-18.tar.gz

- Download MD5 sum: e170147da25e1d5f72721ffc46fe4e06

- Download size: 48 KB

- Estimated disk space required: 1.1 MB

- Estimated build time: less than 0.1 SBU

### efibootmgr Dependencies

#### Required

efivar-39 and popt-1.19

## Installation of efibootmgr

Build efibootmgr with the following commands:

    make EFIDIR=LFS EFI_LOADER=grubx64.efi

This package does not have a test suite.

Now, as the `root` user:

    make install EFIDIR=LFS

## Command Explanations

`EFIDIR=LFS`: This option specifies the distro's subdirectory name under `/boot/efi/EFI`. The building system of this package needs it to be set explicitly.

`EFI_LOADER=grubx64.efi`: This option specifies the name of the default EFI boot loader. It is set to match the EFI boot loader provided by GRUB.

## Using efibootmgr

In LFS, the instructions go over how to install GRUB for UEFI. The process installs the EFI in a hardcoded location searched by most UEFI firmware implementations. If you reinstall GRUB however, GRUB will use this package to install the EFI in a place GRUB prefers, which allows greater control over EFI management. The `--removable` option will no longer be necessary when running grub-install. This package may be necessary in scenarios where the UEFI firmware doesn't look for the hardcoded EFI location. The LFS book addresses this situation.

In order for efibootmgr to work, the EFI variable file system must be mounted beforehand. If you're still in a chroot and haven't rebooted, mount it as the `root` user:

    mountpoint /sys/firmware/efi/efivars ||
      mount -v -t efivarfs efivarfs /sys/firmware/efi/efivars

The EFI variable file system isn't mounted automatically at boot for SysVinit systems, meaning that whenever grub-install or efibootmgr are executed, they will fail. To ensure the file system gets mounted at boot, add the following to `/etc/fstab` as the `root` user:

    cat >> /etc/fstab << "EOF"
    efivarfs /sys/firmware/efi/efivars efivarfs defaults 0 0
    EOF

## Contents

Installed Programs: efibootdump and efibootmgr

### Short Descriptions

efibootdump | is a tool to display individual UEFI boot options, from a file or an UEFI variable
efibootmgr | is a tool to manipulate the UEFI Boot Manager

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