Expand description


An Embassy project.

A lightweight bootloader supporting firmware updates in a power-fail-safe way, with trial boots and rollbacks.

The bootloader can be used either as a library or be flashed directly with the default configuration derived from linker scripts.

By design, the bootloader does not provide any network capabilities. Networking capabilities for fetching new firmware can be provided by the user application, using the bootloader as a library for updating the firmware, or by using the bootloader as a library and adding this capability yourself.

Hardware support

The bootloader supports different hardware in separate crates:

  • embassy-boot-nrf - for the nRF microcontrollers.
  • embassy-boot-stm32 - for the STM32 microcontrollers.

Minimum supported Rust version (MSRV)

embassy-boot requires Rust nightly to compile as it relies on async traits for interacting with the flash peripherals.


This work is licensed under either of

at your option.


Buffer aligned to 32 byte boundary, largest known alignment requirement for embassy-boot.
A flash wrapper implementing the Flash and embedded_storage traits.
BootLoader works with any flash implementing embedded_storage and can also work with different page sizes and flash write sizes.
FirmwareUpdater is an application API for interacting with the BootLoader without the ability to ‘mess up’ the internal bootloader state
FirmwareWriter allows writing blocks to an already erased flash.
Convenience flash provider that uses separate flash instances for each partition.
A region in flash used by the bootloader.
Convenience provider that uses a single flash for all partitions.


Errors returned by bootloader
The state of the bootloader after running prepare.


Extension of the embedded-storage flash type information with block size and erase value.
Trait defining the flash handles used for active and DFU partition