wolfBoot 2.1.0 released

wolfBoot is our secure bootloader designed to provide safety-oriented secure boot for any embedded device. Its success lies in its ability to offer security, efficiency and adaptability to many different use cases, while keeping a simple and safe design. wolfBoot is a solid choice made by many developers securing the boot mechanism on a wide range of embedded devices from every industry.

A new version of wolfBoot (v2.1.0) has been released, which introduces new features, support for more cryptography, ports to new embedded targets and improvements to existing code.

Download wofBoot 2.1.0 from our download page or clone it from github.

Support for custom fields in the manifest header

One of the most requested features by our users consisted in allowing extra parameters in the manifest header of the firmware/software images to be verified.

wolfBoot manifest header consists in a sequence of “TLV” (table-length-value) fields. By default, a signed image’s manifest header contains a SHA digest, the public-key signature itself, and a few extra fields containing metadata relative to the image and the sign process. These fields include a 32-bit version number (used to prevent rollback attacks), a 64-bit timestamp, a digest of the public key needed to verify the signature, a ‘type’ field, used by the bootloader to identify and confirm the algorithms used and the destination partition for the update.

All these fields in the manifest headers, except for the digest and the signature itself, are included in the calculation of the signed digest, which means that their values cannot be altered without compromising the validity of the signature.

The new feature introduced in wolfBoot 2.1.0 consists in three new mechanism that can be used to add new TLVs to the header:

  • –custom-tlv tag len val
    Adds a TLV entry to the manifest header, corresponding to the type identified by “tag”, with length “len“ bytes, and assigns the value “val”.Values can be decimal or hex numbers (prefixed by ‘0x’). This is useful to add numeric values (e.g. with length 1, 2, 4, or 8).
  • –custom-tlv-buffer tag len buffer
    Adds a TLV entry with a buffer in hex format,
    e.g. –custom-tlv-buffer 0x31 6 CCBBAA998877
  • –custom-tlv tag string
    Adds a TLV containing a string of bytes read as ASCII characters from the “string” argument. In this case the length is implicit as the argument is null-terminated.

As usual, these fields can be accessed from wolfBoot custom modules, using the wolfBoot_find_header() parser. This function is included in libwolfboot, which means that the same parser can be invoked on any stored signed image by applications integrating the library.

New signature verification algorithm

ECC521 support has been added, further expanding the range of cryptographic algorithms available for signature verification, bolstering security for a broader spectrum of applications (and did you know that since v2.0 wolfBoot also supports post-quantum signature verification algorithms too?).

Support for new embedded platforms

We facilitate the process to integrate new ports of wolfBoot, which includes the integration of an example application to demonstrate secure boot and update out-of-the-box, with a single build command. This version introduces support for new embedded targets:

  • Renesas RZ2NL
  • Microchip SAM E51
  • NXP MCXA-153
  • NXP i.MX-RT1040

Improvements and enhancements

Version 2.1.0 addresses various bugs and introduces enhancements for existing platforms and target-specific mechanisms.

For targets supporting the DUALBANK option, i.e. the ability to swap the mapping of two “banks” inside the same flash memory support, we added some additional checks to ensure that wolfBoot copies (or “forks”) itself to the second bank only once in the lifetime of the bootloader.

For those use-cases with backup disabled, we have simplified the update mechanism, which also improved the reliability of the update across power-failures.

We have fixed an issue in the wolfTPM integration code, which was preventing the policy from being properly sealed. This issue is only affecting those configurations including the `WOLFBOOT_TPM_SEAL` option introduced in version 2.0.0.

Contacts Us

Let us know what features you value the most, what platforms you would like to see our code running on, or just tell us your story about secure-boot in your embedded systems.
If you have questions about any of the above, please contact us at facts@wolfSSL.com or call us at +1 425 245 8247.

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TLS and Secure Boot in the EU Cyber Resilience Act

As of June 2024, the EU Cyber Resilience Act (CRA) is a pending piece of legislation that has been approved by the European Parliament and is waiting on adoption by the Council of the European Union. Once the act comes into force, manufacturers will have 36 months to apply the rules. It aims to tackle the challenges of cyber security in the EU and “safeguard consumers and businesses buying or using products or software with a digital component”. The act will require that any product sold in the EU with a digital component will adhere to stricter cyber security regulations. Products will have to be secure by default, have a way to apply security updates, have a clear vulnerability process, and define a product life cycle among other requirements.

The CRA requires that all communications are secure. We recommend using secure protocols such as SSL/TLS and SSH instead of trying to develop your own solution. These protocols provide privacy, integrity, and authentication across unsecure networks. They protect against unauthorized access and protect the confidentiality of the transmitted information.

To provide security updates to devices in the field, we recommend using wolfBoot’s Over-The-Air (OTA) update feature. This allows you to provide security updates in compliance with the CRA. wolfBoot provides a highly reliable, transport-agnostic firmware update mechanism.

Over at wolfSSL we take vulnerabilities very seriously. We investigate them immediately and fixes are always developed within days of an initial report. We implement rigorous security testing and code review to ensure the best quality releases possible.

With wolfSSL you can be sure that your products will meet the CRA requirements. For more questions about how to comply with the CRA, or if you have questions about any of the above, please write to us at facts@wolfSSL.com or call us at +1 425 245 8247.

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wolfBoot vs u-boot: Comparing Secure Boot Solutions for Embedded Systems

While working on wolfBoot, many people ask us, how is it different from u-boot, and how does it compare to it if I am designing a secure boot strategy for my embedded systems based on microprocessors.

While taking the same role in embedded systems, wolfBoot and u-boot are two very different projects.

As bootloaders, they are responsible for initializing the hardware, loading the operating system kernel into memory and then executing it. Bootloaders are typically stored in a non-volatile memory like ROM or flash memory and are the first piece of software to run when a device is powered on or reset.

However, their design, code structure, modularity and core responsibilities are far from each other. Let’s find out by looking at the history of the two projects.

The rise of embedded Linux

U-Boot, short for “Das U-Boot,” is an open source bootloader commonly used in embedded systems, particularly in devices like mobile phones and network equipment. Its origins date back to 1999, when the bootloader was originally developed for the PowerPC-based systems. It has since been ported to many other architectures, including ARM and x86.

U-Boot is highly configurable and customizable, allowing developers to adapt it to various hardware configurations and requirements. It provides a command-line interface (CLI) for interacting with the bootloader during the boot process, allowing users to modify boot parameters, load additional software at runtime and even connect to a network to download new images. In addition to its primary role as a bootloader, U-Boot often includes additional features such as support for multiple filesystems, network booting, firmware updates, and diagnostic tools, making it a versatile and powerful tool in embedded system development. Its open-source nature also fosters a strong community of developers contributing to its ongoing development and improvement.

U-Boot is definitely feature rich, flexible and has lived up to its name for so many years, as the most popular generic-purpose bootloader for embedded systems within the range of microprocessors it supports. Throughout the past decades, U-Boot played a significant role in making embedded Linux systems more accessible and widespread. Its versatility and compatibility with diverse hardware architectures contributed to the popularity and success of embedded Linux in various applications, from consumer electronics to industrial automation.

The advent of IoT and its security challenges

With the advent of the Internet of Things (IoT) and the proliferation of connected devices, security concerns in embedded systems became more pronounced. High-profile attacks like the “Mirai” botnet, which exploited vulnerabilities in IoT devices, underscored the importance of securing firmware and boot processes. In response to the growing demand for secure boot solutions, the Internet Engineering Task Force (IETF) started to work on standardizing guidelines for secure boot mechanisms in embedded devices, publishing a draft document which was later on published as RFC9019 in 2021.

wolfBoot has been inspired in the first place by the many successful attempts of wolfSSL customers integrating wolfCrypt public-key verification mechanisms in custom bootloader solutions. This process however would consume a lot of time and resources, which could have been otherwise applied to more central features in their products, if only a solution would have been available to secure the boot mechanism. wolfBoot was then initially developed in 2018, using the draft document from IETF to define its core guidelines.

RFC9019 emphasizes the importance of establishing a secure root of trust and ensuring the integrity of the boot process from the hardware level onwards. It advocates for the use of cryptographic techniques, including public key ciphers such as RSA and ECC, for authentication and verification of firmware images and bootloader components. By using public key cryptography, embedded systems can verify the authenticity and integrity of firmware images before execution, mitigating the risk of unauthorized code execution and firmware tampering.

Additionally, RFC9019 recommends the use of small, robust parsers for processing and verifying configuration files, cryptographic keys, and digital signatures. Small parsers help reduce the attack surface and minimize the risk of vulnerabilities such as buffer overflows or parsing errors. By following these recommendations, embedded systems can enhance their security posture and resilience against sophisticated attacks targeting the boot process and firmware integrity.

A new era of safety-critical, connected systems

In recent years, there has been a proliferation of safety-critical systems that are either connected to the internet or accessible via private networks. This trend extends to various domains, including aerospace, automotive, healthcare and industrial automation. Examples include space systems, autonomous vehicles, medical devices, and industrial control systems. As safety-critical systems become increasingly interconnected, the need for robust security mechanisms, including secure boot, becomes a requirement. These systems are not only subject to safety requirements but also face cybersecurity threats from malicious actors seeking to exploit vulnerabilities and compromise their operation.

The convergence of safety and security considerations poses unique challenges for developers and operators of safety-critical systems. In addition to meeting stringent safety standards and certifications (e.g., DO-178C for avionics, ISO 26262 for automotive), they must also ensure compliance with security standards and best practices to protect against cyber threats and ensure system integrity. Additionally, international regulations are getting stricter every year to enforce traceability of code that is related to security in such scenarios.

wolfSSL offers a range of products that are meeting the needs for certified security that can run in compliance with safety regulations for any specific market. This is where wolfBoot excels among all competitors. A safe bet for cutting the costs towards secure boot in safety-critical embedded systems. wolfCrypt and wolfBoot have been DO-178 certified to DAL A level.

Quantum computers: new challenges to traditional cryptography

While U-Boot offers RSA-based cryptographic options, wolfBoot sets itself apart by leveraging the FIPS 140-2 certified WolfCrypt, a robust and trusted cryptography engine that adheres to the highest security standards. WolfCrypt not only provides support for a wide range of cryptographic algorithms but also offers compatibility with hardware security modules (HSMs), including Trusted Platform Modules (TPMs).

Out of the box, wolfBoot supports a comprehensive set of public key cryptography ciphers, including ECC up to ECC521, RSA up to RSA4096, ED25519, ED448, LMS, and XMSS. This diverse range of cryptographic algorithms ensures flexibility and future-proofing, allowing developers to choose the most suitable algorithms for their specific security requirements.

In the context of long-life systems where the bootloader is immutable, many projects have just started using post-quantum cryptography (PQC). As quantum computing technology advances, traditional cryptographic algorithms like RSA and ECC may become vulnerable to attacks, posing a significant risk to the security of systems relying on them. By incorporating PQC algorithms such as LMS and XMSS, wolfBoot ensures that even with the evolution of quantum computing, the secure boot process remains resilient and future-proof. This proactive approach to security is crucial for safeguarding the integrity and longevity of systems operating in environments where firmware updates are infrequent or impractical. By embracing PQC, wolfBoot offers peace of mind and assurance that the secure boot process will remain robust and secure throughout the lifecycle of the system, providing long-term protection against evolving threats and vulnerabilities.

Secure boot: what really matters

We have analyzed how the two projects have started and evolved with two different goals in the mind of their developers. But what aspects really matter in today’s secure boot solutions? The answer is not easy. U-Boot has so many supported features that could be compared to an operating system, and as we have seen the importance of flexibility in the evolution of embedded Linux systems in the past. wolfBoot is small in size, safety oriented and focuses primarily on the secure boot capabilities. When designing a secure boot strategy, a few key indicators should be taken into consideration:

  • Bootloader’s main purpose: U-Boot aims to be a portable and flexible generic bootloader, while wolfBoot is designed primarily as the main building block for secure boot mechanisms, providing specific countermeasures against attackers having different levels of access to the target system. By default, no user interaction is provided on purpose, to reduce the attack surface as much as possible.
  • Quality of cryptographic engine: wolfBoot is built on top of wolfCrypt, the best tested open source cryptography engine in existence. This means that the algorithms provided to secure the boot process are reliable, certified, transparent and supported by a team of professional developers.
  • Code size: more code certainly means more features, but also more vulnerabilities, higher cost of maintenance, which can easily become unaffordable when safety regulations are added to the picture. wolfBoot guarantees the lowest possible costs related to safety certifications
  • Safety by design: wolfBoot’s compile-time predictability guarantees consistent behavior across different builds and environments. This reliability is invaluable in ensuring the system behaves as expected under all conditions.
  • Post-Quantum cryptography: Quantum computers leverage principles of quantum mechanics to parallelize computations at a scale far exceeding those of classical computers. This computational power poses a significant threat to traditional cryptographic algorithms, which rely on the difficulty of certain mathematical problems for their security. Post-Quantum Cryptography (PQC) seeks to develop cryptographic algorithms that remain secure even in the presence of quantum adversaries. PQC algorithms are designed to withstand attacks from both classical and quantum computers, ensuring long-term security in the post-quantum era. wolfBoot provides support for LMS and XMSS.

Hybrid boot chain

Are you still a big fan of u-boot unique features and flexibility? So are we! If you still want to use any of the features u-boot offers but you want to secure your boot mechanisms, then multi-stage, hybrid solutions may be for you. A hybrid approach can be adopted where the bootloaders coexist in separate stages. In this scenario, wolfBoot can serve as the initial secure bootloader responsible for securely loading and verifying the subsequent stages, including U-Boot images.

wolfBoot can be deployed as the early-stage bootloader responsible for initializing the hardware, performing the initial boot sequence, and verifying the integrity and authenticity of subsequent bootloader stages. It securely loads and verifies the authenticity of the next bootloader stages, in this case including the U-Boot image, using cryptographic signatures and trusted keys stored securely within the system. Once the U-Boot image is verified, wolfBoot hands over control to U-Boot, allowing it to execute with the assurance that it has been securely loaded and verified by wolfBoot.

While U-Boot provides advanced features and flexibility, its complexity can introduce potential vulnerabilities. If vulnerabilities or security issues are discovered in the running U-Boot image, wolfBoot can securely update the U-Boot image with a patched version or a newer release. This ensures that the system remains protected against emerging threats and vulnerabilities without compromising its advanced features.


The comparison between wolfBoot and U-Boot reveals distinct strengths tailored to different needs. U-Boot boasts extensive device support and a well-established feature rich codebase, making it ideal for systems requiring flexibility and connectivity from the very initial stages. On the other hand, wolfBoot shines in security, with lightweight design and certified cryptography ensuring system integrity and low costs of maintenance, making it a perfect fit for all secure-boot requirements across all embedded systems.

In those scenarios where ensuring the integrity of the boot process and validating the authenticity of firmware are crucial, wolfBoot’s lightweight design and certified cryptography are definitely a solid choice: wolfBoot defines the path to securing the boot process for safety-critical embedded systems of the future.

Have questions about your boot strategy? Contact us at facts@wolfSSL.com or +1 425 245 8247!

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wolfBoot: secure boot and more | Unique features to assist and optimize firmware updates

Secure boot. Simple, compact, safe.

wolfBoot is the universal secure bootloader designed for embedded systems. Its main task is to ensure that only a trusted firmware image can run on the target device, as indicated by RFC9019. To do so, it uses signature verification on the firmware image every time the device starts or when a firmware update is received, OTA or through any custom transport.
wolfBoot relies on wolfCrypt cryptographic engine to support the widest range of
options for signature verification algorithms, including ECC-256, RSA up to 4096 bit, Ed25519 and Ed448, and up to post-quantum algorithms such as LMS/HSS and XMSS
Thanks to a wide choice of hardware security modules and crypto co-processors supported by wolfCrypt, wolfBoot can offload all cryptographic operations to dedicated hardware components when available, cutting down boot time and run-time resources.

Support for Post-quantum cryptography

wolfBoot’s support for Post-Quantum Cryptography (PQC) firmware authentication introduces a robust layer of security to embedded systems, ensuring resilience against emerging threats posed by quantum computing advancements. Leveraging schemes like Leighton-Micali Signature (LMS) with Hash-based Merkle Signature Scheme (HSS) or eXtended Merkle Signature Scheme (XMSS), as well as its multi-tree variant, XMSS^MT, wolfBoot secures its firmware authentication mechanism against potential quantum attacks. By integrating these advanced techniques into the bootloader, wolfBoot ensures the integrity of firmware updates for future-proof systems, against the constantly evolving cryptographic attacks.

Secure boot for all systems

wolfBoot does not depend on any specific libraries, except for wolfCrypt. It does not rely on any operating system environment, driver, platform or toolchains.
wolfBoot can secure the entire boot process of any standalone applications as well as complex operating systems, from small class-I microcontrollers up to Rich Execution Environments, on a wide range of microcontrollers and processors architectures (ARM, x86, PowerPc, RISC-V, x86 and more).
Native ports are available for the majority of common embedded targets and evaluation boards. In cases where a native port isn’t readily accessible, wolfSSL extends its engineering services to prioritize porting efforts, ensuring compatibility across virtually any platforms.

Key management tools

The key command line tools, ‘sign’ and ‘keygen’ (for Windows, Linux, MacOS), distributed along with wolfBoot, follow the development of all the features supported by the bootloader to the latest version. They are easy to use, widely documented, and simple to integrate with any deploy mechanism and back-end update services.

Retrofitting existing non-secure bootloaders

Already using your very own bootloader in your existing project? Do not worry. wolfBoot can be integrated with your current solution, by including one single .c file to your old bootloader code.
For existing bootloaders lacking support for secure boot, wolfBoot can in fact be effortlessly integrated as a library, exposing an API for verifying the authenticity and integrity of firmware. This integration enables the utilization of host tools for key management and firmware signing, leveraging the compatibility of wolfBoot’s manifest header for streamlined firmware update processes.

Roll-back: the bootloader “rescue” mode

wolfBoot stores a copy of the old firmware that gets replaced during the update. Mistakes can happen when building or transmitting a firmware update: even if the firmware is trusted and authenticated by wolfBoot it might still introduce bugs and issues in the field that may prevent the device from being reachable again. For this reason, wolfBoot implements a mechanism that requires the firmware to confirm that the system is working as expected after the update. In absence of this confirmation, at the next reboot wolfBoot considers the update as failed, and restores the original image from the backup taken during the update.

Use any external storage, with built-in confidentiality

Some microcontrollers may not have enough flash space to accommodate two versions of the firmware in the internal FLASH. The only requirement on these systems is normally that only the current executing firmware image should be stored in FLASH, where it can be eXecuted in Place (XiP). Most systems don’t support XiP on external storage supports, but that space can still be allocated to store updates and host the swap space required by wolfBoot to perform the update.

Thanks to a transparent, generic external flash interface, wolfBoot can use any external non-volatile memory support to host update and swap partitions, maximizing the space available in the internal FLASH for the running software.

Neighbor systems can host a virtual partition for the wolfBoot target, using any communication bus to implement remote, emulated memory access.

Encryption and decryption is done at runtime by wolfBoot when accessing these external storage devices for writing and reading, respectively. This mechanism prevents wiretapping or intercepting the firmware images when they are transferred on the BUS (SPI, CAN, Uart,…) that connects to the storage device.

Examples distributed with wolfBoot showcase this feature, with common SPI FLASH targets, and emulated remote storage, on a neighbor system via UART.

HSM support, wolfTPM integration, measured boot

wolfBoot inherits from wolfCrypt the capability to access hardware-assisted functionality offered by Hardware Security Modules (HSMs).

Through wolfTPM‘s integration, wolfBoot strengthens the security of firmware updates but also establishes a robust foundation for safeguarding critical assets and maintaining the trustworthiness of embedded systems. Through wolfTPM’s support, wolfBoot enables measured boot processes, ensuring the integrity of the entire boot chain and providing robust protection against tampering and unauthorized modifications of both hardware and software components. wolfTPM facilitates the implementation of advanced security policies, utilizing Platform Configuration Registers (PCRs) to unlock secrets and enforce access controls in accordance.

Self-update: can a secure bootloader update itself?

wolfBoot offers the possibility to authenticate and install a newer version of itself. A special update package can be created with the key tools, containing an update for the bootloader itself. wolfBoot will parse, authenticate and install the update by temporarily executing a copy of itself in RAM.

Incremental updates: faster OTA transfers with “delta updates”

wolfBoot supports incremental updates, based on a specific older version. Thesign tool can create a small “patch” that only contains the binary difference between the version currently running on target and the update package, a ‘delta update’ package. This package is processed by wolfBoot to reconstruct a complete image of the resulting update. The authenticity of the update is verified twice: first when the package is received before applying the patch, and then after the patch is applied, every time the new firmware is staged for boot.

Where has wolfBoot been ported so far?

  • STM32: nearly all models (STM32C0, STM32F0, STM32G0, STM32L0, STM32F4, STM32L4, STM32L5, STM32H5, STM32H7, STM32U5, STM32WB)
  • NXP: LPC54xxx, i.MX-RT10xx, K64F, K83F, MCXA, P1020, T1024, T2080
  • Microchip: SAM R21, SAM E51, PSoC6
  • Renesas: RA6M4, RX72N, RZN2L
  • Nordic: nRF52
  • TI “Hercules” TMS570
  • SiFive: HiFive1 RISCV RV32 microcontroller
  • Cortex-A Microprocessors: Xilinx Ultrascale Zynq+, Raspberry PI
  • x86_64bit: as UEFI application
  • x86_64 Intel Tigerlake: native BIOS replacement using Intel FSP

Porting wolfBoot to a new target is easy. Our HAL API consists of only six mandatory functions to be implemented to perform target-specific clock initialization and interact with the non-volatile memory containing the signed software images.

What feature would you like to see in the next release of wolfBoot? Contact us at facts@wolfSSL.com with any comments or questions!

Check out our GitHub page for the full documentation, and to stay up to date with our latest developments. And while you are there, consider giving the wolfBoot project a star!

If you have questions about any of the above, please contact us at facts@wolfSSL.com or call us at +1 425 245 8247

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wolfBoot support for the Xilinx Zynq UltraScale+ MPSoC

wolfBoot support for the Xilinx UltraScale+ was added in 2020 and is a direct U-Boot replacement for improved security.

wolfBoot provides enhanced features compared to U-Boot such as:

  • Firmware integrity and signature verification on each boot
    • Image integrity checking SHA2-256 or SHA3-384.
    • Validation of the signature using ECC P256/P384, RSA (2048-bit or 3072-bit), ED25519 and LMS or XMSS.
  • Multiple boot partition support
    • Rollback to last known working or fail-safe “golden” image on failure
  • TPM 2.0 Support
    • Measured Boot (PCR’s)
    • Sealing secret to unlock or decrypt a storage device
  • Root of trust options
    • Onboard eFUSES
    • Public key embedded in wolfBoot partition
    • TPM 2.0 NV (supported with wolfTPM)
  • Delta/Differential updates using bentley-mcilroy scheme
  • Encrypted updates using AES CFB or ChaCha20/Poly1305

Additional wolfBoot Features:

  • QSPI, SDMC and eMMC boot support
  • ELF (32 and 64) loader support
  • FDT (Flattened Device Tree) support for fixups
  • AARCH64 EL1/EL3 support

We have included a full example for building with Xilinx SDK and integrating into the FSBL chain of trust. Also creation of the flash boot.bin image with boot.bif and bootgen.

Tested support with bare-metal, QNX, GreenHills Integrity OS and Linux/Fedora.
24×7 support available


If you have questions about any of the above, please contact us at facts@wolfSSL.com or call us at +1 425 245 8247.

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wolfBoot support for the STM32C0 in 2024

We have added wolfBoot support for the new STM32C0. This is a low cost MCU similar to the STM32G0 based on a Cortex-M0 (48MHz). It is a very low cost general purpose 32-bit MCU with up to 32KB flash and 12KB RAM.

Our wolfBoot secure bootloader is the only solution available for this platform thanks to our small code size. Most STM32 parts are supported with wolfBoot out of the box.

The default STM32C0 configuration uses RSA 2048-bit and SHA2-256 and is less than 10KB. This leaves 10KB for the application partition, 10KB for the update partition and one 2KB sector for swap.

STM32C0 documentation and build steps can be found here.

See our video series with ST for a tutorial on using wolfBoot.

wolfBoot Features:

  • Written in C for bare-metal use
  • Small footprint to run on small embedded devices
  • Memory safety (no malloc/free)
  • Support for on-board or external SPI flash
  • Simple partitioning and header scheme
  • Abstracted HAL design for CPU speed and flash
  • Bootloader handles swapping and loading of partitions
  • Key tools for key generation/import and signing
  • Encrypted updates
  • Delta updates (only differences)

Signature algorithms supported:

  • ECC (SECP256R1,SECP384R1)
  • RSA (2048/3072/4096)
  • ED25519
  • ED448
  • Post Quantum LMS and XMSS

Firmware image integrity using hash digest:

  • SHA2-256
  • SHA2-384
  • SHA3-384

Flexible partition scheme determined at build-time:

  • Bootloader (10-30KB)
  • Application
  • Update
  • Swap (1 sector)
  • And custom partition ID’s

Reliable Firmware update mechanism:

  • Independent from the update transport mechanism
  • Fallback to a previous version when the update fails
  • Resume interrupted swap operations during update, in case of power failure

Support for STM hardware crypto acceleration:

  • ST33TP* TPM 2.0 using wolfTPM

If interested in trying our wolfBoot on the STM32C0 or curious about post-quantum signature support in wolfBoot please contact facts@wolfSSL.com or call us at +1 425 245 8247.

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wolfBoot Support for Renesas RZ/N2L

wolfBoot currently support both Renesas RA6M4 and RX72N MCUs. Supporting other Renesas MCUs for wolfBoot should not be difficult. We are considering the addition of Renesas RZ/N2L support for wolfBoot, which will build on our existing support at the wolfSSL and wolfCrypt level for Renesas RZ/N2L.

The Renesas RZ/N2L uses a high-performance Arm Cortex-R52 core to easily add network functionality onto industrial equipment and machines. The RZ/N2L is supported by an open and flexible ecosystem concept – the Flexible Software Package (FSP), built on FreeRTOS – and is expandable to use other RTOS and middleware solutions.

If you are interested in wolfBoot support on the RZ/N2L or have questions about any of the above, please contact us at facts@wolfSSL.com or call us at +1 425 245 8247.

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wolfBoot v2.0.0 intel x86_64 support

wolfBoot v2.0.0 introduced support for the Intel x86-64 bit architecture by leveraging the Intel Firmware Support Package (Intel FSP) and several new exciting and interesting features: TPM integration, Multiboot2/ELF support, PCI support, AHCI support, SATA security features, and others.

On Intel x86_64, wolfBoot uses a dual stage design. In the first stage, It initializes the memory and the hardware with the help of Intel FSP. Intel FSP allows BIOS and bootloader developers to focus on the critical features and broad support without worrying about the hardware initialization details. After the memory and silicon initialization, wolfBoot enumerates and configures all PCI devices in the system.

In the second stage, when the hardware is up and ready, wolfBoot does the necessary steps to read, decrypt, verify, and safely boot the main application. We added support for AHCI controller, SATA disks and ATA security commands: the main application can now be stored in a password-locked hard drive!

In both stages, wolfBoot verifies each component loaded, either from system ROM or from the hard disk, plus the TPM support allows very interesting scenarios. First, it enables TPM-assisted measured boot: each component loaded into the system is “measured”, taking part in an integrity proof managed inside the TPM itself so that certain operations are allowed only if the system is in a trustful state. The TPM can store (“seal”) secrets that can be recovered (“unsealed”) only if the system is in a precise state. If compromised software is running on the target, the secret never leaves the TPM.

In wolfBoot we leverage this by sealing the disk password (randomly generated at the first boot) in the TPM and binding the unsealing to a precise state of the system. If the loaded components are compromised or if the disk is removed from the device for direct tampering, the disk can’t be unlocked at all!

Once the disk is unlocked, it’s time to load the application in the right place and communicate the current hardware situation before booting. wolfboot supports the Multiboot2 standards to communicate with the main application and it supports the Executable and Linkable Format (ELF) format, one of the most ubiquitous object file formats for binary distribution, to load the application in the right places into the memory. As it supports memory virtualization, the application can be loaded anywhere in the address space, even above the 4GB limit.

And, as always, all current features of wolfBoot such as verified boot, OTA firmware secure update with power-fail tolerance, delta updates, encrypted firmware, and post-quantum firmware verification, will be directly available on the Intel x86-64 architecture.

All these new features are supported on the VX3060 Kontron board and can be tested on QEMU, but new hardware will be supported soon. If you have a new Intel-based board you would like to have supported or for any other comments, feedback or questions, don’t hesitate to contact us at facts@wolfSSL.com or call us at +1 425 245 8247.

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