esp-idf-sys based projects

Wrong Xtal Frequency

Using a 26 Mhz crystal instead of a 40 MHz requires modifying the sdkconfig. Add the following configuration option to your sdkconfig file:


After making this adjustment, execute cargo clean to ensure that the changes are properly incorporated into your project. See sdkconfig section.

When using an esp-idf-sys based project, you should also prefer using cargo-espflash instead of espflash. cargo-espflash integrates with your project and it will flash the bootloader and partition table that is built for your project instead of the default one, see the corresponding cargo-espflash readme section.

If you want to use espflash, you can specify an appropriate bootloader and partition table using --bootloader and --partition-table. You can find the bootloader in target/<your MCU's target folder>/<debug or release depending on your build>/bootloader.bin and partition table in target/<your MCU's target folder>/<debug or release depending on your build>/partition-table.bin

Environment Variable LIBCLANG_PATH Not Set

thread 'main' panicked at 'Unable to find libclang: "couldn't find any valid shared libraries matching: ['', 'libclang-*.so', '*', 'libclang-*.so.*'], set the `LIBCLANG_PATH` environment variable to a path where one of these files can be found (invalid: [])"', /home/esp/.cargo/registry/src/

We need libclang for bindgen to generate the Rust bindings to the ESP-IDF C headers. Make sure you have sourced the export file generated by espup, see Set up the environment variables.

Missing ldproxy

error: linker `ldproxy` not found
  = note: No such file or directory (os error 2)

If you are trying to build a std application ldproxy must be installed. See std Development Requirements

cargo install ldproxy

sdkconfig.defaults File is Updated but it Doesn't Appear to Have Had Any Effect

You must clean your project and rebuild for changes in the sdkconfig.defaults to take effect:

cargo clean
cargo build

The Documentation for the Crates Mentioned on This Page is out of Date or Missing

Due to the resource limits imposed by, internet access is blocked while building documentation. For this reason, we are unable to build the documentation for esp-idf-sys or any crate depending on it.

Instead, we are building the documentation and hosting it ourselves on GitHub Pages:

A Stack Overflow in Task main has Been Detected

If the second-stage bootloader reports this error, you likely need to increase the stack size for the main task. This can be accomplished by adding the following to the sdkconfig.defaults file:


In this example, we are allocating 7 kB for the main task's stack.

How to Disable Watchdog Timer(s)?

Add to your sdkconfig.defaults file:


Recall that you must clean your project before rebuilding when modifying these configuration files.