MCUboot release notes

• MCUboot release notes
  • Version 2.5.0
    • Upgrade notes
    • New features
    • Bug fixes
    • Board and SoC support
    • imgtool
    • Pending questions
  • Version 2.4.0
  • Version 2.3.0
  • Version 2.2.0
  • Version 2.1.0
  • Version 2.0.0
    • About this release
  • Version 1.10.0
    • About this release
    • Security fixes
  • Version 1.9.0
    • About this release
    • Security fixes
  • Version 1.8.0
    • About this release
    • Security fixes
  • Version 1.7.0
    • About this release
    • Zephyr-RTOS compatibility
  • Version 1.6.0
    • About this release
    • Security issues addressed
    • Zephyr-RTOS compatibility
  • Version 1.5.0
    • About this release
    • Known issues
  • Version 1.4.0
    • About this release
  • Version 1.3.1
    • About this release
  • Version 1.3.0
    • About this release
  • Version 1.2.0
    • About this release
    • Known issues
  • Version 1.1.0
    • About this release
    • Known issues
  • Version 1.0.0
    • About this release
    • Known issues
  • Version 0.9.0
    • About this release
    • Known issues

Version 2.5.0

This release adds support for Mbed TLS 4.x and TF-PSA-Crypto, experimental logical sectors for the swap modes, a raw binary transport and an inactivity timeout for serial recovery, and multiple verification keys in Zephyr builds. Zephyr users of USB DFU, CDC ACM serial recovery or RAM load need to update their configuration; see the upgrade notes. It also hardens image validation and the handling of image encryption keys.

Upgrade notes

• The Mbed TLS submodule has moved from ext/mbedtls to ext/mbedtls-3.6.0 (still Mbed TLS 3.6.0). If you build a port that uses the in-tree copy, such as the standalone Espressif port, run git submodule update --init --recursive after updating. The old ext/mbedtls directory is no longer used and can be removed.
• Serial recovery: On Zephyr, CDC ACM serial recovery (CONFIG_BOOT_SERIAL_CDC_ACM) now uses Zephyr’s USB device-next stack, and USB is only started when recovery is entered. The legacy CONFIG_USB_DEVICE_* settings no longer apply. Set the USB descriptors with the new CONFIG_BOOT_SERIAL_CDC_ACM_VID, CONFIG_BOOT_SERIAL_CDC_ACM_PID, CONFIG_BOOT_SERIAL_CDC_ACM_MANUFACTURER_STRING and CONFIG_BOOT_SERIAL_CDC_ACM_PRODUCT_STRING options. Their defaults (product ID 0x0004, product string “CDC ACM serial recovery”) differ from before, so update any host tooling that matches on them. The new stack also makes the bootloader larger; check that it still fits its partition.
• Serial recovery: On Zephyr, UART serial recovery (CONFIG_BOOT_SERIAL_UART) and the UART log backend (CONFIG_LOG_BACKEND_UART) can no longer share a UART, and such a build now fails with an error. Point the zephyr,uart-mcumgr chosen node at a separate UART, or disable the UART log backend.
• Serial recovery: On Zephyr, CONFIG_BOOT_SERIAL_MAX_RECEIVE_SIZE must now be at least CONFIG_BOOT_MAX_LINE_INPUT_LEN. Smaller values are rejected when the configuration is processed.
• Zephyr: This release follows changes made on Zephyr’s main branch after Zephyr 4.4.0, including the reworked boot banner, the removal of CONFIG_PSA_CRYPTO_CLIENT and the rename of CONFIG_STM32_MEMMAP. Use it with a Zephyr version newer than 4.4.0. See also the pending questions at the end of this section.
• Zephyr: USB DFU now uses Zephyr’s USB device-next stack and is configured the same way as serial recovery. CONFIG_BOOT_USB_DFU enables USB DFU, and the entrance methods CONFIG_BOOT_USB_DFU_WAIT and CONFIG_BOOT_USB_DFU_GPIO are now independent options that can be enabled together. CONFIG_BOOT_USB_DFU_NO has been removed. If you use USB DFU, set CONFIG_BOOT_USB_DFU=y together with at least one entrance method. The legacy CONFIG_USB_DFU_* and CONFIG_USB_DEVICE_* settings no longer apply: use CONFIG_BOOT_USB_DFU_PERMANENT_DOWNLOAD and the new CONFIG_BOOT_USB_DFU_VID, CONFIG_BOOT_USB_DFU_PID, CONFIG_BOOT_USB_DFU_MANUFACTURER_STRING and CONFIG_BOOT_USB_DFU_PRODUCT_STRING options, whose defaults match the old ones. Downloaded images go to the secondary slot.
• Zephyr: RAM load (CONFIG_BOOT_RAM_LOAD and CONFIG_SINGLE_APPLICATION_SLOT_RAM_LOAD) now takes the RAM region to load images into from a mcuboot,image-ram chosen devicetree node. Setting CONFIG_BOOT_IMAGE_EXECUTABLE_RAM_START and CONFIG_BOOT_IMAGE_EXECUTABLE_RAM_SIZE by hand is deprecated and only possible when that node is missing. Add the chosen node to your board overlay.
• Zephyr: CONFIG_MULTIPLE_EXECUTABLE_RAM_REGIONS_DEFAULT_FILE and the built-in default boot_get_image_exec_ram_info() have been removed. Builds with CONFIG_MULTIPLE_EXECUTABLE_RAM_REGIONS must now provide their own boot_get_image_exec_ram_info().
• Zephyr: MCUboot no longer replaces Zephyr’s boot banner, which changed after Zephyr 4.4. The *** Booting MCUboot ... *** line is now printed after Zephyr’s own banner instead of before it, so update anything that parses boot output. The line is controlled by CONFIG_MCUBOOT_BOOT_BANNER, which is enabled by default when CONFIG_BOOT_BANNER is, but no longer requires it.
• Zephyr: The STM32 external flash configurations now use CONFIG_FLASH_STM32_NOR_MEMMAP, following its rename in Zephyr from CONFIG_STM32_MEMMAP. Rename the option in your own configuration files.
• Zephyr: SOC_FLASH_0_ID and SPI_FLASH_0_ID have been removed from the Zephyr port’s sysflash.h. The flash device of each slot is now taken from its devicetree partition. Out-of-tree code that used these macros must use the devicetree partition macros instead.
• Zephyr: CONFIG_MCUBOOT_CLEANUP_RAM now clears the RAM region of the zephyr,sram chosen devicetree node instead of the region set by CONFIG_SRAM_BASE_ADDRESS and CONFIG_SRAM_SIZE. If your board sets those options to a different region, check which RAM is cleared before the application starts.
• Espressif: The Espressif port now uses the ESP-IDF v6.0.0 HAL. Building the standalone port requires ESP-IDF v6.0 sources.
• Espressif: The bootloader’s RAM layout has changed on all SoCs. A new dram_loader_seg region holds data used while the application is loaded, and the other bootloader regions have moved. The application image must not load anything into the bootloader’s iram_loader_seg, dram_loader_seg or dram_seg regions. Check your OS linker script against the updated memory maps in docs/readme-espressif.md.
• Espressif: The default ESP32-C6 bootloader.conf no longer enables virtual eFuses. Builds that use it now program the real eFuses. To keep emulating them in flash, set CONFIG_EFUSE_VIRTUAL and the related options in your configuration.
• Espressif: The default console baud rate on ESP32-C2 is now 74880.
• NuttX: MCUboot no longer initialises the board through boardctl(BOARDIOC_INIT). Board initialisation must now be done by the NuttX kernel (for example with NuttX’s CONFIG_BOARD_LATE_INITIALIZE).

New features

• Added experimental support for logical sectors. A non-zero MCUBOOT_LOGICAL_SECTOR_SIZE makes the swap algorithms work in units of that size rather than the device’s hardware sectors. The size must be a power of two and a multiple of the hardware erase size, and each slot must be a multiple of it. With MCUBOOT_VERIFY_LOGICAL_SECTORS, MCUboot checks the logical layout against the flash at boot and, if they do not match, boots the primary slot without upgrading. On Zephyr, set CONFIG_MCUBOOT_LOGICAL_SECTOR_SIZE and CONFIG_MCUBOOT_VERIFY_LOGICAL_SECTORS.
• Added MCUBOOT_USE_CUSTOM_CRYPTO, which lets a port supply its own hash, signature and encryption primitives (another library, a hardware accelerator or a vendor SDK) without modifying MCUboot. See docs/custom_crypto.md.
• Added MCUBOOT_BOOT_TMPBUF_SZ, which lets a port set the size of the buffer used to read an image while hashing it (default 256 bytes). A larger buffer means fewer flash reads, which helps on flash that is not memory mapped. A smaller one saves RAM.
• The Mbed TLS crypto backend (MCUBOOT_USE_MBED_TLS) and PSA image encryption now also build against Mbed TLS 4.x and TF-PSA-Crypto 1.x. The Mbed TLS header layout is detected automatically. MCUBOOT_MBEDTLS_CRYPTO_IN_PRIVATE_SUBDIR can override the detection. With PSA crypto and MCUBOOT_FIH_PROFILE_HIGH, the fault injection random delay now uses psa_generate_random().
• AES key wrap image encryption (MCUBOOT_ENCRYPT_KW) can now use the PSA Crypto backend (MCUBOOT_USE_PSA_CRYPTO). It needs a PSA implementation that provides psa_unwrap_key(), and has been tested with TF-M.
• Serial recovery: Added a raw binary SMP transport, CONFIG_BOOT_SERIAL_RAW_PROTOCOL, which drops the base64, length, CRC and console framing of SMP over console. It uses less flash and RAM and transfers faster, but needs a binary-capable serial link. It matches Zephyr’s CONFIG_UART_MCUMGR_RAW_PROTOCOL. By default, a partly received packet is discarded after CONFIG_BOOT_SERIAL_RAW_PROTOCOL_INPUT_TIMEOUT_MS without new data (CONFIG_BOOT_SERIAL_RAW_PROTOCOL_INPUT_TIMEOUT).
• Serial recovery: Added the optional MCUmgr parameters command (CONFIG_BOOT_MGMT_MCUMGR_PARAMS), which reports the SMP buffer size and count so that clients can choose the best fragment size. It requires CONFIG_BOOT_MAX_LINE_INPUT_LEN to stay at its default of 128.
• Serial recovery: Added CONFIG_BOOT_SERIAL_INACTIVITY_TIMEOUT. When serial recovery was entered through CONFIG_BOOT_SERIAL_BOOT_MODE or CONFIG_BOOT_SERIAL_WAIT_FOR_DFU, it resets the device once no MCUmgr command has arrived for the set time. An abandoned upload then no longer leaves the device in recovery. The default of 0 keeps the previous behaviour.
• Serial recovery: On Zephyr, the UART receive interrupt now reads data in batches rather than one byte at a time, cutting per-byte overhead during uploads. The batch size is set with CONFIG_BOOT_SERIAL_UART_RX_BATCH_SIZE (default 512).
• Zephyr: CONFIG_BOOT_SIGNATURE_KEY_FILE now accepts a comma-separated list of PEM files, each embedded as a verification key. A development bootloader can then accept both production- and development-signed images, for example. Every key after the first must be public-key only, and all keys must be of the same type.
• Zephyr: Added CONFIG_BOOT_IMAGE_JUMP_HOOKS, which calls a user-supplied boot_image_jump_hook() after an image has been selected and just before jumping to it. The hook can inspect or change the boot response, for example to set flash access rights or remap memory.

Bug fixes

• Hardened image validation against malformed image headers and TLVs. TLV lengths are now checked against the bounds of the TLV area. An image whose header describes more data than its slot holds is rejected before it is hashed.
• Hardened the handling of image encryption keys. With serial recovery, the AES key and any decrypted image data are now wiped from memory after an encrypted upload is validated or decrypted in place. The TinyCrypt backend now wipes the AES key schedule when a decryption context is released, as the other backends already did.
• Fixed a hang at boot with MCUBOOT_DATA_SHARING_BOOTINFO and hardware rollback protection when the security counter of an image could not be read. The shared boot information now records the security counter of every image, not only the first one found.
• Fixed the secondary slot address check done by MCUBOOT_VERIFY_IMG_ADDRESS (without MCUBOOT_CHECK_HEADER_LOAD_ADDRESS) on Cortex-M. It read the wrong vector table entry, so a valid update could be rejected and erased, or an image linked for the wrong address accepted.
• Fixed bootstrap (MCUBOOT_BOOTSTRAP) in swap-move and swap-offset modes. It could read beyond the flash area and erase the wrong sectors, and it copied the whole slot instead of only the image.
• The watchdog is now fed while an image is hashed. Before, a large image on slow or external flash could trigger a watchdog reset during validation.
• Fixed the build with MCUBOOT_HW_ROLLBACK_PROT_LOCK.
• Fixed a stack overflow when checking split images (split_go()) in builds with MCUBOOT_SIGN_EC384 or MCUBOOT_SHA512.
• Fixed decryption of RSA-OAEP encrypted images with the Mbed TLS backend built against TF-PSA-Crypto (Mbed TLS 4.x). The private key was misparsed, so the image could not be decrypted.
• Fixed image encryption with the PSA Crypto backend in builds that use MCUboot’s generic CMake file, such as TF-M. The PSA encryption code was not built, and defining both MCUBOOT_USE_PSA_CRYPTO and MCUBOOT_USE_MBED_TLS caused a compile error. Encryption schemes other than EC256 and X25519 no longer need Mbed TLS headers.
• docs/PORTING.md now lists all the flash functions a port must provide. flash_area_get_sector(), flash_device_base() and flash_area_id_from_image_slot() were required but not documented.
• Serial recovery: The slot info command reported wrong image IDs for upload when direct image upload was disabled.
• Serial recovery: An upload with an image number beyond the number of images is now rejected with an error instead of writing to another flash area. After a failed request, an encrypted image is no longer decrypted in place.
• Serial recovery: Fixed a possible division by zero during in-place decryption of an uploaded encrypted image when the flash driver fails to report the sector layout.
• Serial recovery: On Zephyr, direct image upload (CONFIG_MCUBOOT_SERIAL_DIRECT_IMAGE_UPLOAD) now works for image IDs 7 to 16. Before, uploads to the slots of images 4 to 8 failed.
• Serial recovery: On Zephyr, the wait for a DFU command (CONFIG_BOOT_SERIAL_WAIT_FOR_DFU) now ends after CONFIG_BOOT_SERIAL_WAIT_FOR_DFU_TIMEOUT. Before, it could last several times longer.
• Serial recovery: On Zephyr with CONFIG_BOOT_SERIAL_WAIT_FOR_DFU, the console was initialised a second time when recovery was also entered through boot mode or because there was no application. With CDC ACM this made the bootloader panic, and on a UART it lost received bytes.
• Serial recovery: Fixed a link error on Zephyr with image encryption and deferred logging.
• Serial recovery: On ports other than Zephyr and Espressif, such as Mynewt, a base64 decoding error in a received frame is now detected. Before, the error went unnoticed.
• Zephyr: With CONFIG_BOOT_MAX_IMG_SECTORS_AUTO, the maximum sector count now takes the slots of every image into account, not only image 0. The erase and write sizes of the secondary slot are now read from the flash it is actually on.
• Zephyr: Fixed the trailer size that sysbuild reserves at the end of the application for swap-move and swap-offset. Swap-offset could build an application too large to swap, and swap-move reserved a sector more than needed.
• Espressif: Fixed the build of the standalone port with serial recovery (CONFIG_ESP_MCUBOOT_SERIAL), which lacked an Mbed TLS source file.
• Mynewt: Fixed the build of serial recovery without image encryption.

Board and SoC support

• Zephyr: Added configurations for the nRF93M1DK, the MR-NAVQ95B (Cortex-M7 core, with MCUboot placed in the boot container by default), the FRDM-MCXL255 and the KIT_PSE84_EVAL, and SoC configurations for the ESP32-C5, ESP32-C61, ESP32-P4 and ESP32-S31.
• Zephyr: On the nRF54H20 application core, multithreading is now enabled so that MRAM power-down can be held off while MCUboot writes to MRAM, which avoids stalled writes.
• Espressif: Added initial support for the ESP32-C5, ESP32-C61 and ESP32-P4. The ESP32-C61 uses ECDSA image signing.

imgtool

• imgtool now requires Python 3.8 or later. This also fixes key export commands, which failed on Python 3.8 and 3.9.
• Added imgtool keyinfo, which reports whether a PEM file holds a key pair or only a public key. With --require, it fails if the kind does not match, which build systems can use as a check.
• Added --name-suffix to imgtool getpub and imgtool getpubhash, which appends a suffix to the generated C or Rust symbol names so that several keys can be embedded in one image.
• Public-key-only PEM files are now supported by imgtool getpub, imgtool getpubhash and imgtool verify. imgtool sign given a public-only PEM now fails with a clear error.

Pending questions

These questions are open for this release candidate and will be settled before the final 2.5.0 release. If your testing answers one of them, please report it on the MCUboot GitHub issue tracker.

• Zephyr: Does this release still build and work with Zephyr 4.4.x, or only with Zephyr newer than 4.4.0? The in-tree STM32 external flash configurations already need the newer Zephyr.
• Espressif: The standalone port’s flash build target now calls esptool with its hyphenated option names (write-flash, --before default-reset, --after no-reset). Which esptool versions accept them? If flashing fails, please report your esptool version.
• NuttX, Mbed: Extra flash_area_close() calls were removed from the swap code that resumes an interrupted swap and that reads an image’s size. On NuttX and Mbed, closing a flash area releases the device, so these calls may have caused swap upgrade failures with 2.4.0. If you saw such failures, does this release candidate fix them?
• Mynewt: The Mynewt port is built in CI, but the core maintainers no longer test it on hardware. Mynewt users, please test this release candidate, especially serial recovery.

Version 2.4.0

• Added support for using an inbuilt (compiled-in) key in Zephyr builds.
• Added support for using an external PSA crypto library backend (a non-mbedTLS PSA backend) in Zephyr builds.
• Added a Kconfig choice in Zephyr builds to select between Mbed TLS legacy crypto and the PSA API for RSA operations. Legacy crypto remains the default since the PSA API increases the flash footprint and is not acceptable for all targets.
• Added ECDSA support to the Zephyr port using mbedTLS.
• BOOT_SIGNATURE_TYPE_RSA no longer selects RSA key exchange support, since MCUboot only requires RSA for signature verification.
• Use the new MBEDTLS_VERSION_4_x Kconfig boolean in Zephyr builds to select between Mbed TLS 3.x legacy crypto and the TF-PSA-Crypto 1.x backend.
• Automatically enable TEST_RANDOM_GENERATOR in Zephyr builds when PSA crypto is enabled and no entropy driver is available, since MBEDTLS_PSA_CRYPTO_LEGACY_RNG no longer selects it implicitly.
• Renamed CONFIG_MBEDTLS_CFG_FILE usage to follow the rename in Zephyr.
• Renamed nRF54H Kconfig symbol usage to follow the rename in Zephyr.
• imgtool: added a new --custom-tlv-file option that works like --custom-tlv but reads the TLV value from a binary file instead of taking it on the command line.
• imgtool: dumpinfo now supports a -f/--format option to select between human, yaml and json output. The defaults remain backwards compatible (human for stdout, yaml when writing to a file).
• imgtool: dumpinfo can now read Intel hex (.hex) files in addition to binary files.
• Zephyr’s sysbuild hooks have been reworked to support arbitrary-named MCUboot images, also allowing for multiple MCUboot builds in a single sysbuild project to update different images with estimated image overhead sizes.
• Zephyr builds now use partition macros without the FIXED_ prefix, allowing MCUboot to be used on devices that use fixed-partitions and zephyr,memory-mapped compatibles.
• Use the DT_REG_ADDR() and DT_REG_SIZE() devicetree macros to obtain the target load area address range, allowing nodes that rely on a devicetree ranges property to be used.
• Removed the forced CONFIG_BOOT_MAX_IMG_SECTORS for Espressif targets so that auto detection can take place.
• Added support for placing image slots in sub-partition devicetree nodes when computing MCUboot image overhead.
• Improved the Zephyr CMake support for finding NVM devices, including reading the write and erase block sizes from the device.
• Added support for an ext_flash_app variant on the stm32h7s3xx, allowing chainloading applications from external flash while MCUboot runs from internal flash.
• Updated the nrf52840 board overlay bindings to use the new zephyr,memory-mapped binding, and added missing ranges properties on a few board overlays.
• Espressif: separated the do_boot path so that RISC-V based Espressif SoCs no longer fall through to the wrong do_boot implementation.
• Espressif: updated the default bootloader.conf files to reflect the default flash layout configuration for most Espressif boards on Zephyr.
• Espressif: added a default SoC configuration for ESP32-H2 so that DRAM usage does not overflow.
• Mbed: added flash_area_get_sector to fix an undefined reference for Mbed CE.
• Mbed: fixed the MCUBOOT_SWAP_SAVE_ENCTLV configuration option by switching to the canonical name and correcting the macro name.
• Mynewt: improved the BOOTUTIL configuration so that only bootutil_public.c is built for non-bootloader builds, allowing applications to skip bootloader-only syscfgs.
• Fixed image size validation to include the ih_protect_tlv_size field.
• Fix: Corrected the copy size calculation when bootstrapping and swapping using MCUBOOT_SWAP_USING_MOVE. Previously, the primary region size was used, which could be larger than the secondary region, when using the optimal region sizes. Now, the size of the secondary region (excluding the swap sector and sectors needed for swapping) is used, ensuring only the valid image area is copied. This prevents potential over-copying and related issues during image upgrade or bootstrap operations.
• Fixed image_validate so that the offset of the swap-using-move sector is included when pure mode is used in swap-offset.
• Fixed image_ed25519 to no longer call mbedTLS public key functions when MCUBOOT_BUILTIN_KEY is enabled.
• Fixed the definition of bootutil_find_key when MCUBOOT_BYPASS_KEY_MATCH is set and MCUBOOT_HW_KEY is not.
• Fixed typos and incorrect types/pointer indirection in boot_serial_encryption.
• Added the missing swap-offset source file to the bootutil CMake list, and fixed the RAM load source file which was using Zephyr-specific Kconfigs to decide whether it should be included.
• RISCV targets in swap mode will no longer erroneously attempt to load the image to RAM and will boot the image directly, as this is fully supported by RISCV and looks to have been an error in a previous code submission.
• Fixed devicetree compatible property handling in CMake so that matching soc-nv-flash works for nodes whose compatible property contains multiple strings.
• Fixed the regression where the mbedTLS include path was not added to the MCUboot build, breaking RSA support with encryption.
• Fixed an extra . in a log message.
• Call LOG_PANIC() before jumping to the application so log backends have an opportunity to flush in-flight messages before the jump.
• Capture log events that were previously lost very early or very late in the boot process: the deferred logging thread now starts with K_NO_WAIT and is woken in zephyr_boot_log_stop() so it drains pending messages before MCUboot jumps to the application.
• Reworked the Zephyr CMake support to fix many issues, including a missing project name, casing fixes, deduplicated statements, and stopped abusing zephyr_library_* functions where MCUboot is not actually a library.
• Added error codes to several bootutil loader log messages and reformatted others to fit on fewer lines for easier readability and grepping.
• Removed the outdated hello-world Zephyr sample, since Zephyr’s tree contains a sysbuild MCUboot sample that should be used instead.
• Fixed the ext/nrf/cc310_glue include path to drop the deprecated non-zephyr/ prefix.
• Fixed Kconfig options that were leaking outside of the MCUboot menu.
• Fixed a missing tsa-crypto dependency twister error.
• Updated the design documentation to correct an outdated comment that suggested the TLV type field is 8-bit when it is actually 16-bit.

Version 2.3.0

• Added support for booting Cortex-R5 images
• Add support for cleaning up the Cortex-R core before final jumping
• Aligned the project security policy with the TrustedFirmware.org security policy.
• Fixed imgtool dependency on click package version.
• Enabled support for ram-load revert mode, which functions using the same logic as direct-xip revert mode but loads the executable image to ram.
• Add cache flush after write/erase operations to avoid getting invalid data when these are followed by read operation.
• Fix image wrong state after swap-scratch when hardware flash encryption is enabled. When hardware flash encryption is enabled, force expected erased value (0xFF) into flash when erasing a region, and also always do a real erase before writing data into flash.
• Move the Virtual eFuse offset in flash configuration from hardcoded value to .conf file.
• Fixed issue in boot_scramble_regions, where incorrect boundary check would cause function to attempt to write pass a designated flash area.
• Fixed issue in image_validate when MCUBOOT_HASH_STORAGE_DIRECTLY is enabled for platforms with NVM memory that does not start at 0x00.
• Fixed issue in image_validate when BOOT_SIGNATURE_TYPE_PURE is enabled for platforms with NVM memory that does not start at 0x00.
• Fixed serial recovery with progressive erase for MCUboot modes of single updatable slot (MCUBOOT_SINGLE_APPLICATION_SLOT, MCUBOOT_FIRMWARE_LOADER, MCUBOOT_SINGLE_APPLICATION_SLOT_RAM_LOAD) which was previously failing due to attempting to access non-existent image status fields.
• Fixed issue with imgtool when trying to compress images with no header padding requested.
• Fixed issue with swap using offset when mininmal erase was enabled that did not offset the erase to the second sector and wrongly used the (empty) first sector of the secondary slot.
• Switched to picolibc as the default C library in Zephyr.
• Fixed wrong define specifying 2 slots in single loader mode instead of just 1
• Fixed wrong slot ID in hook calls from serial recovery.
• Fixed issues with serial recovery not building/not working/faulting.
• Swap using offset now includes the size of the unprotected TLV area which was wrongly missing before, this requires extra space in the swap status as the data is not part of the image header
• Control over compilation of unprotected TLV allow list has been exposed using MCUBOOT_USE_TLV_ALLOW_LIST mcuboot configuration identifier.
• Fixed issue with platforms that have MCUBOOT_SUPPORT_DEV_WITHOUT_ERASE set that did not scramble (delete) data sections from the trailer that should have been deleted.
• Fixed issue with boot_scramble_region escaping flash area due to error in the range check.
• A few changes to make vscode nicer, including a default package to build at the top level, and ignoring some of the cache files from vscode.
• Zephyr builds are now using Kconfig CONFIG_MCUBOOT_BOOT_MAX_ALIGN to set the MCUBOOT_BOOT_MAX_ALIGN.
• Fixed issue with checking pin reset not checking for single flag in Zephyr.
• imgtool verify when using a public ed25519 key has been fixed to work rather than show an invalid key type not matching the TLV record error.
• Zephyr signature and encryption key file path handling has now been aligned with Zephyr, this means values can be specified in multiple .conf file and the one that last set it will be the set value. This also means that key files will no longer be found relative to the .conf file and will instead be found relative to the build system APPLICATION_CONFIG_DIR variable, though the key file strings are now configured which allows for using escaped CMake variables to locate the files, for example with \${CMAKE_CURRENT_LIST_DIR} to specify a file relative to the folder that the file is in.

• Watchdog support in Zephyr has been reworked and fixed to allow installing a timeout (with a configurable value) before starting it. The default timeout is set to 1 minute and this feature has been enabled by default. 3 Kconfig options have been added which control how the watchdog is used in MCUboot:

  • CONFIG_BOOT_WATCHDOG_SETUP_AT_BOOT controls setting up the watchdog in MCUboot (if not set up, it can still be set, if the driver supports this non-compliant behaviour).
  • CONFIG_BOOT_WATCHDOG_INSTALL_TIMEOUT_AT_BOOT controls if a timeout is installed at bootup or not.
  • CONFIG_BOOT_WATCHDOG_TIMEOUT_MS sets the value of the timeout in ms.
• In addition, Zephyr modules can now over-ride the default watchdog functionality by replacing the weakly defined functions mcuboot_watchdog_setup and/or mcuboot_watchdog_feed, these functions take no arguments.
• correct esp32c6 overlay

Version 2.2.0

• Added support for retrieving HW embedded private keys for image encryption (The private key can be retrieved from trusted sources like OTP, TPM.).
• Changed bootutil’s order of events to verify the image header before checking the image.
• Added the bootloader state object to the bootutil boot_is_header_valid() function
• Added optional write block size checking to ensure expected sizes match what is available on the hardware.
• Added optional erase size checking to ensure expected sizes match what is available on the hardware.
• Added debug logs for zephyr to output discrepencies in erase and write block sizes in dts vs actual hardware configuration at run-time.
• When using swap with scratch, the image is now decrypted when copying from the scratch partition to the primary slot. Therefore, the scratch partition doesn’t contain plaintext firmware data anymore.
• Added verification for supported IDF-based HAL version.
• Fixed missing macro for XMC flash devices on ESP32-S3
• Extended image loader header to include RTC/LP RAM, DROM and IROM segments.
• Fixed errors when building for thingy52, thingy53 and nrf9160dk boards.
• Fixed chain load address output log message for RAM load mode in Zephyr
• Fixed issue for swap using move whereby a device could get stuck in a revert loop despite there being no image in the secondary slot
• Fixed clash when using sysbuild with other applications (i.e. tests) using the name mcuboot
• imgtool: added initial sanity tests for imgtool commands,
• imgtool: added and enabled unittests in GitGub workflow,
• Fixed wrong maximum application size calculation when operating in swap using move mode
• Added additional images max size support to shared data function
• Fixed issue with serial recovery image list wrongly using number of images as the number of slots and not returning complete information for 1 updateable image
• Added slot info command support to serial recovery mode
• Fixed issue with serial recovery variables not being correctly initialised to default values which could cause some commands to do unexpected operations
• Added a new swap using offset algorithm which is set with MCUBOOT_SWAP_USING_OFFSET. This algorithm is similar to swap using move but avoids moving the sectors in the primary slot up by having the update image written in the second sector in the update slot, which offers a faster update process and requires a smaller swap status area
• Added support for automatically calculating the maximum number of sectors that are needed for a build by checking the erase sizes of the partitions using CMake for Zephyr. This behaviour can be reverted to the old manual behaviour by disabling CONFIG_BOOT_MAX_IMG_SECTORS_AUTO
• Added protected TLV size to image size check in bootutil
• Added Kconfig for decompression support in Zephyr
• Added compressed image flags and TLV to bootutil
• Added support for removing images with conflicting flags in bootutil
• Added support for removing encrypted/compressed images when MCUboot is compiled without support for them
• Added support for devices that do not require erase prior to write operation.
• Add corrections to the max app size calculations.
• Fixed issue with swap using scratch mode that would cause the primary image to be corrupt and unbootable after an update if the device was rebooted whilst the scratch area was being erased.
• Fixed issue with serial recovery if canonical CBOR mode was enabled.
• Fixed issue with serial recovery set image state not checking primary slot images.
• Fixed issue with watchdog not being fed during flash erase operations, which could cause the watchdog to time out on long erase operations and prevent firmware updates from being possible.
• Fix issues related to calculating the maximum image size for a given configuration.
• Fix an issue with sha hash calculations in a loop.
• Fix an issue with the security counter being updated before an image is confirmed.
• Added a contributing guideline.
• Fixed an issue related to referencing the arm-vector table of the application, which caused a jump to the incorrect address instead of the application reset vector for some Zephyr builds when LTO (link time optimization) was enabled.
• Fixed issue with trailer and swap status sizes wrongly being included in single slot/firmware loaded modes which wrongly reduced the maximum allowable firmware sizes.
• Fixes for Zephyr 4.1 and MPU/SYSMPU renaming
• Fix support for MCX-N9XX with Zephyr.

Version 2.1.0

• Boot serial: Add response to echo command if support is not enabled, previously the command would have been accepted but no response indicating that the command is not supported would have been sent.
• Added support for using builtin keys for image validation (available with the PSA Crypto API based crypto backend for ECDSA signatures).
• Enforce that TLV entries that should be protected are. This can be disabled by defining ALLOW_ROGUE_TLVS
• bootutil: Fixed issue with comparing sector sizes for compatibility, this now also checks against the number of usable sectors (which is the slot size minus the swap status and moved up by one sector).
• bootutil: Added debug logging to show write location of swap status and details on sectors including if slot sizes are not optimal for a given board.
• Update ptest to support test selection. Ptest can now be invoked with list to show the available tests and run to run them. The -t argument will select specific tests to run.
• Allow sim tests to skip slow tests. By setting MCUBOOT_SKIP_SLOW_TESTS in the environment, the sim will skip two tests that are very slow. In one instance this reduces the test time from 2 hours to about 5 minutes. These slow tests are useful, in that they test bad powerdown recovery, but are inconvenient when testing other areas.
• Zephyr: Fixes support for disabling instruction/data caches prior to chain-loading an application, this will be automatically enabled if one or both of these caches are present. This feature can be disabled by setting CONFIG_BOOT_DISABLE_CACHES to n.
• Zephyr: Fix issue with single application slot mode, serial recovery and encryption whereby an encrypted image is loaded and being wrongly treated as encrypted after decryption.
• Zephyr: Add estimated image footer size to cache in sysbuild.
• Added firmware loader configuration type support for Zephyr, this allows for a single application slot and firmware loader image in the secondary slot which is used to update the primary image (loading it in any way it sees fit e.g. via Bluetooth).
• Zephyr: Remove deprecated ZEPHYR_TRY_MASS_ERASE Kconfig option.
• Zephyr: Prevent MBEDTLS Kconfig selection when tinycrypt is used.
• Zephyr: Add USB CDC serial recovery check that now causes a build failure if console is enabled and device is the same as the USB CDC device.
• Zephyr: Add USB CDC serial recovery check that now causes a build failure if the main thread priority is below 0 (cooperative thread), this would prevent USB CDC from working as the driver would not have been able to fire callbacks.
• Use general flash operations to determine the flash reset vector. This improves support a bit for some configurations of external flash.
• fix a memory leak in the HKDF implementation.
• Zephyr: Added a MCUboot banner which displays the version of MCUboot being used and the version of zephyr. This can be disabled by setting CONFIG_MCUBOOT_BOOT_BANNER=n which will revert back to the default zephyr boot banner.

Version 2.0.0

Note that this release, 2.0.0 is a new major number, and contains a small API change in the interface between mcuboot and the platform. All platforms contained within the MCUboot tree have been updated, but any external platforms will have to be adjusted. The following commit makes the API change, in the function boot_save_shared_data.

commit 3016d00cd765e7c09a14af55fb4dcad945e4b982
Author: Jamie McCrae <jamie.mccrae@nordicsemi.no>
Date:   Tue Mar 14 12:35:51 2023 +0000

    bootutil: Add active slot number and max app size to shared data

About this release

• Add error when flash device fails to open.
• Panic bootloader when flash device fails to open.
• Fixed issue with serial recovery not showing image details for decrypted images.
• Fixes issue with serial recovery in single slot mode wrongly iterating over 2 image slots.
• CDDL auto-generated function code has been replaced with zcbor function calls, this now allows the parameters to be supplied in any order.
• Added currently running slot ID and maximum application size to shared data function definition.
• Make the ECDSA256 TLV curve agnostic and rename it to ECDSA_SIG.
• imgtool: add P384 support along with SHA384.
• espressif: refactor after removing IDF submodule
• espressif: add ESP32-C6, ESP32-C2 and ESP32-H2 new chips support
• espressif: adjustments after IDF v5.1 compatibility, secure boot build and memory map organization
• Serial recovery image state and image set state optional commands added
• imgtool: add ‘dumpinfo’ command for signed image parsing.
• imgtool: add ‘getpubhash’ command to dump the sha256 hash of the public key
• imgtool’s getpub can print the output to a file
• imgtool can dump the raw versions of the public keys
• Drop ECDSA P224 support
• Fixed an issue with boot_serial repeats not being processed when output was sent, this would lead to a divergence of commands whereby later commands being sent would have the previous command output sent instead.
• Fixed an issue with the boot_serial zcbor setup encoder function wrongly including the buffer address in the size which caused serial recovery to fail on some platforms.
• zcbor library files have been updated to version 0.7.0
• Reworked boot serial extensions so that they can be used by modules or from user repositories by switching to iterable sections.
• Removed Zephyr custom img list boot serial extension support.
• (Zephyr) Adds support for sharing boot information with application via retention subsystem
• Zephyr no longer builds in optimize for debug mode, this saves a significant amount of flash space.
• Reworked image encryption support for Zephyr, static dummy key files are no longer in the code, a pem file must be supplied to extract the private and public keys. The Kconfig menu has changed to only show a single option for enabling encryption and selecting the key file.
• Serial recovery can now read and handle encrypted seondary slot partitions.
• Serial recovery with MBEDTLS no longer has undefined operations which led to usage faults when the secondary slot image was encrypted.
• espressif: allow the use of a different toolchain for building

Version 1.10.0

The 1.10.0 release of MCUboot contains…

About this release

• Various fixes to boot serial.
• Various fixes to the mbed target.
• Various fixes to the Espressif native target.
• Various fixes to the Zephyr target.
• Workflow improvements with Zephyr CI.
• Add multi image support to the espressif esp32 target.
• Improvements and corrections to the simulator.
• Improve imgtool, including adding 3rd party signing support.
• Various fixes to the mynewt target.
• Various fixes to the nuttx target.
• Dates to dependencies for doc generation.
• Add downgrade prevention for modes using swap.
• Various general fixes to the boot code.
• Prefer swap move on zephyr if the scratch partition is not enabled.
• Upgrade fault-injection hardening, improving cases injections are detected.
• Add a new flash api flash_area_get_sector, along with support for each target, that replaces flash_area_sector_from_off. This is a step in cleaning up the flash API used by MCUboot.

Security fixes

There are no security vulnerabilities reported on the MCUboot code for this release. There have been several updates to the dependencies in the Ruby code used to generate the documentation. This should only affect users that generate their own documentation.

Version 1.9.0

The 1.9.0 release of MCUboot contains various bug fixes, improves support on some recent targets, and adds support for devices with a write alignment larger than 8.

This change introduces a potentially incompatible change to the format of the image trailer. If BOOT_MAX_ALIGN is kept at 8, the trailer format does not change. However, to support larger write alignments, this value can be increased, which will result in a different magic number value. These targets were previously unsupported in MCUboot, so this change should not affect any existing targets. The change has been tested with a BOOT_MAX_ALIGN up to 32 bytes.

About this release

• Add native flash encryption to Espressif targets
• Numerous documentation improvements
• Increase coverage of large images in the simulator
• Add stm32 watchdog support
• Add support for the mimxrt685_evk board
• Add support for “partial multi-image booting”
• Add support for clear image generation with encryption capability to imgtool
• Fix Zephyr when CONFIG_BOOT_ENCRYPTION_KEY_FILE is not defined
• Remove zephyr example test running in shell. The Go version is primary and much more featureful.
• imgtool: make --max-align default reasonable in most cases.
• Implement the mcumgr echo command in serial boot mode

Security fixes

Version 1.8.0

The 1.8.0 release of MCUboot contains numerous fixes, and adds support for the NuttX RTOS, and the Espressif ESP32 SDK.

About this release

• Add support for the NuttX RTOS.
• Add support for the Espressif ESP32 SDK.
• boot_serial changed to use cddl-gen, which removes the dependency on tinycbor.
• Add various hooks to be able to change how image data is accessed.
• Cypress supports Mbed TLS for encryption.
• Support using Mbed TLS for ECDSA. This can be useful if Mbed TLS is brought in for another reason.
• Add simulator support for testing direct-XIP and ramload.
• Support Mbed TLS 3.0. Updates the submodule for Mbed TLS to 3.0.
• Enable direct-xip mode in Mbed-OS port.
• extract bootutil_public library, a common interface for MCUboot and the application.
• Allow to boot primary image if secondary one is unreachable.
• Add AES256 image encryption support.
• Add Multiimage boot for direct-xip and ram-load mode.
• Cargo files moved to top level, now cargo test can be run from the top level directory.
• Fault injection tests use updated TF-M.
• Thingy:53 now supports multi-image DFU.
• ram load and image encryption can be used together, allowing the entire contents of flash to always remain encrypted.

Security fixes

• GHSA-gcxh-546h-phg4 has been published. There is not a fix at this time, but a caution to be sure to follow the instructions carefully, and make sure that the development keys in the repo are never used in a production system.

Version 1.7.0

The 1.7.0 release of MCUboot adds support for the Mbed-OS platform, Equal slots (direct-xip) upgrade mode, RAM loading upgrade mode, hardening against hardware level fault injection and timing attacks and single image mode. There are bug fixes, and associated imgtool updates as well.

About this release

• Initial support for the Mbed-OS platform.
• Added possibility to enter deep sleep mode after MCUboot app execution for cypress platform.
• Added hardening against hardware level fault injection and timing attacks.
• Introduced Abstract crypto primitives to simplify porting.
• Added RAM-load upgrade mode.
• Renamed single-image mode to single-slot mode.
• Allow larger primary slot in swap-move
• Fixed boostrapping in swap-move mode.
• Fixed issue causing that interrupted swap-move operation might brick device if the primary image was padded.
• Abstracting MCUboot crypto functions for cleaner porting
• Droped flash_area_read_is_empty() porting API.
• boot/zephyr: Added watchdog feed on nRF devices. See CONFIG_BOOT_WATCHDOG_FEED option.
• boot/zephyr: Added patch for turning off cache for Cortex M7 before chain-loading.
• boot/zephyr: added option to relocate interrupts to application
• boot/zephyr: clean ARM core configuration only when selected by user
• boot/boot_serial: allow nonaligned last image data chunk
• imgtool: added custom TLV support.
• imgtool: added possibility to set confirm flag for hex files as well.
• imgtool: Print image digest during verify.

Zephyr-RTOS compatibility

This release of MCUboot works with the Zephyr “main” at the time of the release. It was tested as of has 7a3b253ce. This version of MCUboot also works with the Zephyr v2.4.0, however it is recommended to enable CONFIG_MCUBOOT_CLEANUP_ARM_CORE while using that version.

Version 1.6.0

The 1.6.0 release of MCUboot adds support for the PSOC6 platform, X25519 encrypted images, rollback protection, hardware keys, and a shared boot record to communicate boot attestation information to later boot stages. There are bug fixes, and associated imgtool updates as well.

About this release

• Initial support for the Cypress PSOC6 plaformt. This platform builds using the Cypress SDK, which has been added as submodules.
• CBOR decoding in serial recovery replaced by code generated from a CDDL description.
• Add support for X25519 encrypted images.
• Add rollback protection. There is support for a HW rollback counter (which must be provided as part of the platform), as well as a SW solution that protects against some types of rollback.
• Add an optional boot record in shared memory to communicate boot attributes to later-run code.
• Add support for hardware keys.
• Various fixes to work with the latest Zephyr version.

Security issues addressed

• CVE-2020-7595 “xmlStringLenDecodeEntities in parser.c in libxml2 2.9.10 has an infinite loop in a certain end-of-file situation.” Fix by updating a dependency in documentation generation.

Zephyr-RTOS compatibility

This release of MCUboot works the Zephyr “main” at the time of the release. It was tested as of has 1a89ca1238. When Zephyr v2.3.0 is released, there will be a possible 1.6.1 or similar release of Zephyr if needed to address any issues. There also may be branch releases of MCUboot specifically for the current version of Zephyr, e.g. v1.6.0-zephyr-2.2.1.

Version 1.5.0

The 1.5.0 release of MCUboot adds support for encrypted images using ECIES with secp256r1 as an Elliptic Curve alternative to RSA-OAEP. A new swap method was added which allows for upgrades without using a scratch partition. There are also lots of bug fixes, extra simulator testing coverage and some imgtool updates.

About this release

• TLVs were updated to use 16-bit lengths (from previous 8). This should work with no changes for little-endian targets, but will break compatibility with big-endian targets.
• A benchmark framework was added to Zephyr
• ed25519 signature validation can now build without using Mbed TLS by relying on a bundled tinycrypt based sha-512 implementation.
• imgtool was updated to correctly detect trailer overruns by image.
• Encrypted image TLVs can be saved in swap metadata during a swap upgrade instead of the plain AES key.
• imgtool can dump private keys in C format (getpriv command), which can be added as decryption keys. Optionally can remove superfluous fields from the ASN1 by passing it --minimal.
• Lots of other smaller bugs fixes.
• Added downgrade prevention feature (available when the overwrite-based image update strategy is used)

Known issues

• TLV size change breaks compatibility with big-endian targets.

Version 1.4.0

The 1.4.0 release of MCUboot primarily adds support for multi-image booting. With this release, MCUboot can manage two images that can be updated independently. With this, it also supports additions to the TLV that allow these dependencies to be specified.

Multi-image support adds backward-incompatible changes to the format of the images: specifically adding support for protected TLV entries. If multiple images and dependencies are not used, the images will be compatible with previous releases of MCUboot.

About this release

• Fixed CVE-2019-5477, and CVE-2019-16892. These fix issue with dependencies used in the generation of the documentation on github.
• Numerous code cleanups and refactorings
• Documentation updates for multi-image features
• Update imgtool.py to support the new features
• Updated the Mbed TLS submodule to current stable version 2.16.3
• Moved the Mbed TLS submodule from within sim/mcuboot-sys to ext. This will make it easier for other board supports to use this code.
• Added some additional overflow and bound checks to data in the image header, and TLV data.
• Add a -x (or --hex_addr) flag to imgtool to set the base address written to a hex-format image. This allows the image to be flashed at an offset, without having to use additional tools to modify the image.

Version 1.3.1

The 1.3.1 release of MCUboot consists mostly of small bug fixes and updates. There are no breaking changes in functionality. This release should work with Mynewt 1.6.0 and up, and any Zephyr main after sha f51e3c296040f73bca0e8fe1051d5ee63ce18e0d.

About this release

• Fixed a revert interruption bug
• Added ed25519 signing support
• Added RSA-3072 signing support
• Allow ec256 to run on CC310 interface
• Some preparation work was done to allow for multi image support, which should land in 1.4.0. This includes a simulator update for testing multi-images, and a new name for slot0/slot1 which are now called “primary slot” and “secondary slot”.
• Other minor bugfixes and improvements

Version 1.3.0

The 1.3.0 release of MCUboot brings in many fixes and updates. There are no breaking changes in functionality. Many of the changes are refactorings that will make the code easier to maintain going forward. In addition, support has been added for encrypted images. See the docs for more information.

About this release

• Modernize the Zephyr build scripts.
• Add a ptest utility to help run the simulator in different configurations.
• Migrate the simulator to Rust 2018 edition. The sim now requires at least Rust 1.32 to build.
• Simulator cleanups. The simulator code is now built the same way for every configuration, and queries the MCUboot code for how it was compiled.
• Abstract logging in MCUboot. This was needed to support the new logging system used in Zephyr.
• Add multiple flash support. Allows slot1/scratch to be stored in an external flash device.
• Add support for encrypted images.
• Add support for flash devices that read as ‘0’ when erased.
• Add support to Zephyr for the nrf52840_pca10059. This board supports serial recovery over USB with CDC ACM.
• imgtool is now also available as a python package on pypi.org.
• Add an option to erase flash pages progressively during recovery to avoid possible timeouts (required especially by serial recovery using USB with CDC ACM).
• imgtool: big-endian support
• imgtool: saves in intel-hex format when output filename has .hex extension; otherwise saves in binary format.

Version 1.2.0

The 1.2.0 release of MCUboot brings a lot of fixes/updates, where much of the changes were on the boot serial functionality and imgtool utility. There are no breaking changes in MCUboot functionality, but some of the CLI parameters in imgtool were changed (either removed or added or updated).

About this release

• imgtool accepts .hex formatted input
• Logging system is now configurable
• Most Zephyr configuration has been switched to Kconfig
• Build system accepts .pem files in build system to autogenerate required key arrays used internally
• Zephyr build switched to using built-in flash_map and TinyCBOR modules
• Serial boot has substantially decreased in space usage after refactorings
• Serial boot build doesn’t require newlib-c anymore on Zephyr
• imgtool updates:
  • “create” subcommand can be used as an alias for “sign”
  • To allow imgtool to always perform the check that firmware does not overflow the status area, --slot-size was added and --pad was updated to act as a flag parameter.
  • --overwrite-only can be passed if not using swap upgrades
  • --max-sectors can be used to adjust the maximum amount of sectors that a swap can handle; this value must also be configured for the bootloader
  • --pad-header substitutes --included-header with reverted semantics, so it’s not required for firmware built by Zephyr build system

Known issues

None

Version 1.1.0

The 1.1.0 release of MCUboot brings a lot of fixes/updates to its inner workings, specially to its testing infrastructure which now enables a more thorough quality assurance of many of the available options. As expected of the 1.x.x release cycle, no breaking changes were made. From the tooling perpective the main addition is newt/imgtool support for password protected keys.

About this release

• serial recovery functionality support under Zephyr
• simulator: lots of refactors were applied, which result in the simulator now leveraging the Rust testing infrastructure; testing of ecdsa (secp256r1) was added
• imgtool: removed PKCS1.5 support, added support for password protected keys
• tinycrypt 0.2.8 and the Mbed TLS ASN1 parser are now bundled with MCUboot (eg secp256r1 is now free of external dependencies!)
• Overwrite-only mode was updated to erase/copy only sectors that actually store firmware
• A lot of small code and documentation fixes and updates.

Known issues

None

Version 1.0.0

The 1.0.0 release of MCUboot introduces a format change. It is important to either use the imgtool.py also from this release, or pass the -2 to recent versions of the newt tool in order to generate image headers with the new format. There should be no incompatible format changes throughout the 1.x.y release series.

About this release

• Header format change. This change was made to move all of the information about signatures out of the header and into the TLV block appended to the image. This allows
  • The signature to be replaced without changing the image.
  • Multiple signatures to be applied. This can be used, for example, to sign an image with two algorithms, to support different bootloader configurations based on these image.
  • The public key is referred to by its SHA1 hash (or a prefix of the hash), instead of an index that has to be maintained with the bootloader.
  • Allow new types of signatures in the future.
• Support for PKCS#1 v1.5 signatures has been dropped. All RSA signatures should be made with PSS. The tools have been changed to reflect this.
• The source for Tinycrypt has been placed in the MCUboot tree. A recent version of Tinycrypt introduced breaking API changes. To allow MCUboot to work across various platforms, we stop using the Tinycrypt bundled with the OS platform, and use our own version. A future release of MCUboot will update the Tinycrypt version.
• Support for some new targets:
  • Nordic nRF51 and nRF52832 dev kits
  • Hexiwear K64
• Clearer sample applications have been added under samples.
• Test plans for zephyr, and mynewt.
• The simulator is now able to test RSA signatures.
• There is an unimplemented load_addr header for future support for RAM loading in the bootloader.
• Numerous documentation.

Known issues

None

Version 0.9.0

This is the first release of MCUboot, a secure bootloader for 32-bit MCUs. It is designed to be operating system-agnostic and works over any transport - wired or wireless. It is also hardware independent, and relies on hardware porting layers from the operating system it works with. For the first release, we have support for three open source operating systems: Apache Mynewt, Zephyr and RIOT.

About this release

• This release supports building with and running Apache Mynewt and Zephyr targets.
• RIOT is supported as a running target.
• Image integrity is provided with SHA256.
• Image originator authenticity is provided supporting the following signature algorithms:
  • RSA 2048 and RSA PKCS#1 v1.5 or v2.1
  • Elliptic curve DSA with secp224r1 and secp256r1
• Two firmware upgrade algorithms are provided:
  • An overwrite only which upgrades slot 0 with the image in slot 1.
  • A swapping upgrade which enables image test, allowing for rollback to a previous known good image.
• Supports both Mbed TLS and tinycrypt as backend crypto libraries. One of them must be defined and the chosen signing algorithm will require a particular library according to this list:
  • RSA 2048 needs Mbed TLS
  • ECDSA secp224r1 needs Mbed TLS
  • ECDSA secp256r1 needs tinycrypt as well as the ASN.1 code from Mbed TLS (so still needs that present).

Known issues

• The image header and TLV formats are planned to change with release 1.0: https://runtimeco.atlassian.net/browse/MCUB-66