Flashing a RIOT Application - Riot

import Contact from '@components/contact.astro';

After all of the previous sections are completed, we can finally flash some real hardware. In this case, we use an esp32-mh-et-live-minikit development board. The guide should mostly apply to all other boards as well.

:::note Some boards require extra steps to be flashed, such as pressing a button to enter a bootloader or attaching an external programmer. Refer to the documentation of the board to check if extra steps are required. :::

:::tip[Flashing under WSL] If you are using Windows, this assumes that the USB UART bridge of the ESP32 development board has been attached to WSL and VS Code has been launched from within WSL by running code . inside the RIOT repository from the Ubuntu terminal. :::

Open the examples folder
Open the basic folder within examples
Open the default folder within basic
Open the main.c file in the default folder
Select the "Terminal" tab at the bottom
Enter cd ~/RIOT/examples/basic/default to enter the default folder also in the terminal
Run make BOARD=esp32-mh-et-live-minikit compile-commands
- You can replace esp32-mh-et-live-minikit with the name of any other supported board

:::note Did you notice that IntelliSense did not find headers in main.c when you opened it? This should be fixed after the command in 6 has completed. :::

Now run make BOARD=esp32-mh-et-live-minikit BUILD_IN_DOCKER=1 flash term

:::note Tired of typing BOARD=<NAME_OF_THE_BOARD> and BUILD_IN_DOCKER=1? You can add those to the Makefile of your app or run export BOARD=BUILD_IN_DOCKER=1 in the shell. The export will not persist needs to be repeated for every new terminal window. :::

:::tip Running BOARD=<INSERT_TARGET_BOARD_HERE> make info-programmers-supported in your application folder lists the programmers supported by RIOT for the given board. :::

When compiling with BUILD_IN_DOCKER=1, the toolchains distributed in the riot/riotbuild docker image will be used for compilation. This image contains toolchains for all supported RIOT board and is extensively tested in our CI.

The first time you build with BUILD_IN_DOCKER=1, the image is pulled automatically.

This may take a while ...

... until eventually the docker image is pulled and the build will start. Subsequent builds will no longer need to download the toolchain and be a lot quicker.

After building and flashing the firmware has succeeded, a shell will open.

Wait for the boot message to appear.
- The board may boot faster than your PC is able to connect to the serial. If you see nothing after "Welcome to pyterm!" for 5 seconds, try hitting the reset button on the board to boot it again.
You are now connected to the RIOT shell running on the board. Try running the help command to get a list of commands supported by the board.
You can drop out of the RIOT serial by pressing Ctrl + C and return to the Linux shell.

:::tip[Flashing under Windows] It is also possible to install a native Windows flash application and invoke that from within WSL. However, the setup is too board specific to be covered here. Please refer to the documentation of the board you are using. :::

:::caution[Known Issues under Windows] The Linux Kernel in WSL currently has [CONFIG_USB_HIDDEV disabled][wsl-hid-issue]. Hence, programmers using HID as transport do not work for now and fail to flash. The (non-conclusive) list of affected programmers is:

- Atmel/Microchip eDBG
- Atmel/Microchip ICE
- Any ARM CMSIS DAP compatible programmers

The (non-conclusive) list of programmers that work with WSL out of the box is:

- ST-Link (any version), including [cheap clones](https://www.aliexpress.com/wholesale?SearchText=ST-Link+V2)
- Segger J-Link, including the [J-Link EDU Mini](https://www.segger.com/products/debug-probes/j-link/models/j-link-edu-mini/)
- Any serial based bootloader (e.g. ESP boards, Arduino Bootloaders, ...)
- [Black Magic Probe](https://black-magic.org)
- [Jeff Probe](https://flirc.com/more/flirc-jeff-probe-bmp-jtag-black-magic-probe)
- Any other non HID USB programmer


[wsl-hid-issue]: https://github.com/microsoft/WSL/issues/10581

:::