Hello Arthur,
maybe you are speaking about the "minimal" boot method as in https://git.linaro.org/lava/lava-dispatcher.git/tree/lava_dispatcher/actions... I don't have an example here but that just something like - boot: method: minimal os: oe prompts: - <my_prompt>
In order to deploy the overlay on the device, you can use "transfer_overlay" (see https://validation.linaro.org/static/docs/v2/actions-boot.html?#transfer-ove... )
Rgds