Secure boot for 32-bit Microcontrollers!
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utzig Fix overwrite-only encrypted images in sim
Also add overwrite-only + encrypted tests to travis-ci.

Signed-off-by: Fabio Utzig <>
Latest commit 9b7a258 Dec 3, 2018


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This is mcuboot, version 1.2.0

MCUboot is a secure bootloader for 32-bit MCUs. The goal of MCUboot is to define a common infrastructure for the bootloader, system flash layout on microcontroller systems, and to provide a secure bootloader that enables easy software upgrade.

MCUboot is operating system and hardware independent and relies on hardware porting layers from the operating system it works with. Currently, mcuboot works with both the Apache Mynewt, and Zephyr operating systems, but more ports are planned in the future. RIOT is currently supported as a boot target with a complete port planned.

Using MCUboot

Instructions for different operating systems can be found here:


The issues being planned and worked on are tracked using GitHub issues. To participate please visit:

MCUBoot GitHub Issues

Issues were previously tracked on MCUboot JIRA , but it is now deprecated.


Information and documentation on the bootloader are stored within the source.

It was previously also documented on confluence: MCUBoot Confluence however, it is now deprecated and not currently maintained

For more information in the source, here are some pointers:

  • boot/bootutil: The core of the bootloader itself.
  • boot/boot_serial: Support for serial upgrade within the bootloader itself.
  • boot/zephyr: Port of the bootloader to Zephyr
  • boot/mynewt: Mynewt bootloader app
  • imgtool: A tool to securely sign firmware images for booting by mcuboot.
  • sim: A bootloader simulator for testing and regression


Developers welcome!