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sprout/docs/setup/signed/fedora.md
2025-11-12 16:11:13 +01:00

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Setup Sprout for Fedora with Secure Boot

Prerequisites

  • Modern Fedora release: tested on Fedora 43 x86_64.
  • EFI System Partition mounted on /boot/efi (the default)
  • You will need the following packages installed: openssl, mokutil, sbsigntools, efibootmgr

NOTE: Fedora on ARM64 itself does not support Secure Boot consistently.

Step 1: Generate and Install Secure Boot Key

# Create a directory to store the Secure Boot MOK key and certificates.
$ mkdir -p /etc/sprout/secure-boot
# Change to the created directory.
$ cd /etc/sprout/secure-boot
# Generate a MOK key and certificate.
$ openssl req \
    -newkey rsa:4096 -nodes -keyout mok.key \
    -new -x509 -sha256 -days 3650 -subj '/CN=Sprout Secure Boot/' \
    -out mok.crt
# Generate a DER encoded certificate for enrollment.
$ openssl x509 -outform DER -in mok.crt -out mok.cer
# Import the certificate into the Secure Boot environment.
# This will ask you to make a password that will be used during enrollment.
$ mokutil --import mok.cer
# Reboot your machine.
# During boot, MOK enrollment should appear. If it doesn't, ensure you are booting into the shim.
# Press any key to begin MOK management. Select "Enroll MOK".
# Select "View key 0", and ensure the subject says "CN=Sprout Secure Boot".
# If the subject does not match, something has gone wrong with MOK enrollment.
# Press Enter to continue, then select the "Continue" option.
# When it asks to enroll the key, select the "Yes" option.
# Enter the password that you created during the mokutil --import step.
# Select "Reboot" to boot back into your Operating System.

Step 2: Prepare the Secure Boot Environment

# Create a directory for Sprout EFI artifacts.
$ mkdir -p /boot/efi/EFI/sprout

# For x86_64, copy the following artifacts to the Sprout EFI directory.
$ cp /boot/efi/EFI/fedora/shimx64.efi /boot/efi/EFI/sprout/shimx64.efi
$ cp /boot/efi/EFI/fedora/mmx64.efi /boot/efi/EFI/sprout/mmx64.efi

# For aarch64, copy the following artifacts to the Sprout EFI directory.
$ cp /boot/efi/EFI/fedora/shimaa64.efi /boot/efi/EFI/sprout/shimaa64.efi
$ cp /boot/efi/EFI/fedora/mmaa64.efi /boot/efi/EFI/sprout/mmaa64.efi

Step 3: Install Unsigned Sprout

Download the latest sprout.efi release from the GitHub releases page. For x86_64 systems, download the sprout-x86_64.efi file, and for ARM64 systems, download the sprout-aarch64.efi file. Copy the downloaded sprout.efi file to /boot/efi/EFI/sprout/sprout.unsigned.efi on your EFI System Partition.

Step 4: Sign Sprout for Secure Boot

# For x86_64, sign the unsigned Sprout artifact and name it grubx64.efi which is what the shim will call.
$ sbsign \
    --key /etc/sprout/secure-boot/mok.key \
    --cert /etc/sprout/secure-boot/mok.crt \
    --output /boot/efi/EFI/sprout/grubx64.efi \
    /boot/efi/EFI/sprout/sprout.unsigned.efi

# For aarch64, sign the unsigned Sprout artifact and name it grubaa64.efi which is what the shim will call.
$ sbsign \
    --key /etc/sprout/secure-boot/mok.key \
    --cert /etc/sprout/secure-boot/mok.crt \
    --output /boot/efi/EFI/sprout/grubaa64.efi \
    /boot/efi/EFI/sprout/sprout.unsigned.efi

Step 5: Install and Sign EFI Drivers

You will need a filesystem EFI driver if /boot is not FAT32 or ExFAT.

ext4

Most Fedora systems use an ext4 filesystem for /boot, if that is the case, use the ext4 instructions here:

Install the necessary edk2-ext4 package:

# Install the ext4 driver from the package manager.
$ dnf install edk2-ext4

Copy the ext4 driver to /boot/efi/EFI/sprout/ext4.unsigned.efi:

# For x86_64, copy the ext4x64.efi driver to the Sprout EFI directory.
$ cp /usr/share/edk2/drivers/ext4x64.efi /boot/efi/EFI/sprout/ext4.unsigned.efi

# For aarch64, copy the ext4aa64.efi driver to the Sprout EFI directory.
$ cp /usr/share/edk2/drivers/ext4aa64.efi /boot/efi/EFI/sprout/ext4.unsigned.efi
# Sign the ext4 driver at ext4.unsigned.efi, placing it at ext4.efi, which will be used in the configuration.
$ sbsign \
    --key /etc/sprout/secure-boot/mok.key \
    --cert /etc/sprout/secure-boot/mok.crt \
    --output /boot/efi/EFI/sprout/ext4.efi \
    /boot/efi/EFI/sprout/ext4.unsigned.efi

Other Filesystems

If you need another driver, you can download EFI filesystem drivers from EfiFs releases. Copy the driver to /boot/efi/EFI/sprout/DRIVER_NAME.unsigned.efi for signing, then sign it like this:

# Sign your driver, placing it at DRIVER_NAME.efi, which will be used in the configuration.
$ sbsign \
    --key /etc/sprout/secure-boot/mok.key \
    --cert /etc/sprout/secure-boot/mok.crt \
    --output /boot/efi/EFI/sprout/DRIVER_NAME.efi \
    /boot/efi/EFI/sprout/DRIVER_NAME.unsigned.efi

You will add the driver in your Sprout configuration below, like this:

[drivers.DRIVER_NAME]
path = "\\EFI\\sprout\\DRIVER_NAME.efi"

Step 6: Create Sprout Configuration

Write the following to the file /boot/efi/sprout.toml:

# sprout configuration: version 1
version = 1

# load an ext4 EFI driver.
# skip this if you do not have a filesystem driver.
# if your filesystem driver is not named ext4, change accordingly.
[drivers.ext4]
path = "\\EFI\\sprout\\ext4.efi"

# global options.
[options]
# enable autoconfiguration by detecting bls enabled
# filesystems and generating boot entries for them.
autoconfigure = true

Ensure you add the signed driver paths to the configuration, not the unsigned ones. If you do not have any drivers, exclude the drivers section entirely.

Step 7: Configure Sprout Boot Entry

In the following commands, replace /dev/BLOCK_DEVICE with the device that houses your GPT partition table, and PARTITION_NUMBER with the partition number of the EFI System Partition. For example, if your EFI System Partition is /dev/sda1, the BLOCK_DEVICE would be /dev/sda and the PARTITION_NUMBER would be 1

# For x86_64, run this command to add Sprout as the default boot entry.
$ efibootmgr -d /dev/BLOCK_DEVICE -p PARTITION_NUMBER -c -L 'Sprout' -l '\EFI\sprout\shimx64.efi'

# For aarch64, run this command to add Sprout as the default boot entry.
$ efibootmgr -d /dev/BLOCK_DEVICE -p PARTITION_NUMBER -c -L 'Sprout' -l '\EFI\sprout\shimaa64.efi'

Reboot your machine and it should boot into Sprout. If Sprout fails to boot, it should boot into the original bootloader.