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RAUC - Robust Auto-Update Controller

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Packaging status

RAUC controls the update process on embedded Linux systems. It is both a target application that runs as an update client and a host/target tool that allows you to create, inspect and modify update files ("bundles").

Source Code:


Chat: IRC channel #rauc on (bridged to the Matrix channel


  • Fail-Safe & Atomic:
    • An update may be interrupted at any point without breaking the running system.
    • Update compatibility check
    • Atomic bootloader updates (eMMC boot partitions, MBR, GPT)
  • Cryptographic signing and verification of updates using OpenSSL (signatures based on x.509 certificates)
    • Keys and certificates on PKCS#11 tokens (HSMs) are supported
  • Flexible and customizable redundancy/storage setup
    • Symmetric setup (Root-FS A & B)
    • Asymmetric setup (recovery & normal)
    • Application partition, data partitions, ...
    • Allows grouping of multiple slots (rootfs, appfs) as update targets
  • Built-in HTTP(S) streaming mode
    • No intermediate storage on target required
  • Delta-like adaptive update support
    • Transparent selection of download optimization
  • Alternative network delta-streaming mode (using casync tool)
    • chunk-based binary delta updates
    • special bundle format and external chunk store
  • Bundle encryption for multiple recipients
  • Bootloader support:
  • Storage support:
    • read-only filesystems: SquashFS, EROFS, dm-verity protected images, ...
    • read-write filesystems: ext4, VFAT, UBIFS, JFFS2
    • eMMC boot partitions (atomic update)
    • UBI volumes
    • raw NAND flash (using nandwrite)
    • raw NOR flash (using flashcp)
    • MBR partition table
    • GPT partition table
  • Independent from update source
    • Simple webserver (e.g. lighttpd)
    • Software provisioning server (e.g. hawkBit with rauc-hawkbit-updater)
    • USB Stick
  • Controllable via D-Bus interface
  • Supports data migration
  • Network protocol support using libcurl (https, http, ftp, ssh, ...)
  • Several layers of update customization
    • Update-specific extensions (hooks)
    • System-specific extensions (handlers)
    • fully custom update script

Host Features

  • Create and sign update bundles
  • Resign bundles
  • Encrypt bundles
  • Inspect bundle files

Target Features

  • Run as a system service (D-Bus interface)
  • Install bundles
  • View system status information
  • Change status of symmetric/asymmetric/custom slots

Target Requirements

  • Boot state storage
    • GRUB: environment file on SD/eMMC/SSD/disk
    • Barebox: State partition on EEPROM/FRAM/MRAM or NAND flash
    • U-Boot: environment variable
    • EFI: EFI variables
    • Custom: depends on implementation
  • Boot target selection support in the bootloader
  • Enough mass storage for two symmetric/asymmetric/custom slots
  • Storage location and storage space for the bundle:
    • For USB stick update: Sufficent space on the stick for (compressed) bundle, no on-target storage required
    • For HTTP(S) bundle streaming installation: Sufficient space on server, no on-target storage requied
      • For adaptive updates: some on-target storage for meta-data
    • For casync-based updates: temporary on-target storage for downloaded chunks required
    • For external (non-streaming) download: Sufficient temporary on-target storage space for (compressed) bundle
  • Hardware watchdog (optional, but recommended)
  • RTC (optional, but recommended)


Please see the documentation for details.


Host (Build) Prerequisites

  • build-essential
  • meson
  • libtool
  • libdbus-1-dev
  • libglib2.0-dev
  • libcurl3-dev
  • libssl-dev
sudo apt-get install build-essential meson libtool libdbus-1-dev libglib2.0-dev libcurl3-dev libssl-dev

For HTTP(S) streaming support, you also need netlink protocol headers:

sudo apt-get install libnl-genl-3-dev

If you intend to use json-support you also need

sudo apt-get install libjson-glib-dev

Target Prerequisites

Required kernel options (either y or m):

  • CONFIG_BLK_DEV_NBD (for streaming support)
  • CONFIG_DM_CRYPT (for encryption support)
  • CONFIG_CRYPTO_AES (for encryption support)

For using tar archive in RAUC bundles with Busybox tar, you have to enable the following Busybox feature:


Depending on the actual storage type and/or filesystem used, further target tools might be required. The documentation chapter Required Target Tools gives a more detailed list on these.

Building from Sources


RAUC is intended to be built both as a host tool as well as a target tool (service). Therefore it is fully prepared for cross-compilation with meson.

git clone
cd rauc
meson setup build
meson compile -C build # or 'ninja -C build' on meson < 0.54.0

Manual Installation


To prepare RAUC for the target device, it is highly recommended to use an embedded Linux distribution build suite such as Yocto/OE, PTXdist or Buildroot.

On the host system RAUC can be used directly from the build dir, or optionally be installed. On the target instead, installing is highly recommended as it also unpacks service and D-Bus configuration files required to run RAUC properly:

meson install

Running the Test Suite

sudo apt-get install qemu-system-x86 time squashfs-tools
# Optional to run all tests:
# sudo apt-get install faketime casync grub-common openssl softhsm2 opensc opensc-pkcs11 libengine-pkcs11-openssl mtd-utils

Creating a Bundle (Host)

Create a directory with the content that should be installed:

mkdir content-dir/
cp $SOURCE/rootfs.ext4 content-dir/

Create a manifest describing which image to install where together with some meta info:

cat >> content-dir/manifest.raucm << EOF
compatible=FooCorp Super BarBazzer

Let RAUC create a bundle from this:

rauc --cert autobuilder.cert.pem --key autobuilder.key.pem bundle content-dir/ update-2019.01-1.raucb

Starting the RAUC Service (Target)

Create a system configuration file in /etc/rauc/system.conf and start the service process in background:

rauc service &

Installing a Bundle (Target)

To install the bundle (from local storage) on your target device, run:

rauc install update-2023.02-1.raucb

To install a bundle from a webserver (using RAUC's built-in HTTP(S) streaming), run:

rauc install


Fork the repository and send us a pull request.

Please read the Documentation's Contributing section for more details.


Copyright (C) 2015–2024 RAUC project

RAUC is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this source code, see the file named COPYING. If not, see