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Add the possibility to have user bootloader components. This is performed from an application/project, by creating bootloader components. To do so, it is required to create a `bootloader_component` directory containing the custom modules to be compiled with the bootloader. Thanks to this, two solutions are available to override the bootloader now: - Using hooks within a user bootloader component - Using a user defined `main` bootloader component to totally override the old implementation Please check the two new examples in `examples/custom_bootloader` * Closes https://github.com/espressif/esp-idf/issues/7043
50 lines
1.6 KiB
Markdown
50 lines
1.6 KiB
Markdown
# Bootloader override
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(See the README.md file in the upper level for more information about bootloader examples.)
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The purpose of this example is to show how to override the second stage bootloader from a regular project.
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**NOTE**: Overriding the bootloader is not supported with `Makefile` build system, it is only available with `CMake`.
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## How to use example
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Simply compile it:
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```
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idf.py build
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```
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And flash it with the following commands:
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```
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idf.py flash
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```
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This custom bootloader does not do more than the older bootloader, it only prints an extra message on start up:
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```
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[boot] Custom bootloader has been initialized correctly.
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```
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## Organisation of this example
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This project contains an application, in the `main` directory that represents a user program.
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It also contains a `bootloader_components` directory that, as it name states, contains a component that will override the current bootloader implementation.
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Below is a short explanation of files in the project folder.
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```
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├── CMakeLists.txt
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├── main
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│ ├── CMakeLists.txt
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│ └── main.c User application
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├── bootloader_components
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│ └── main
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│ ├── component.mk
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│ ├── CMakeLists.txt
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│ ├── ld/
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│ │ └── ...
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│ └── bootloader_start.c Implementation of the second stage bootloader
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└── README.md This is the file you are currently reading
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```
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As stated in the `README.md` file in the upper level, when the bootloader components is named `main`, it overrides
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the whole second stage bootloader code.
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