I have tried out this example for an advanced bootloader for my ESP32-C3 and I´ve got the example running by using the raw esp-idf in a docker container.
I have integrated the bootloader in the root of my current project under the directory bootloader_components, but it looks like the bootloader isn´t used during the compilation because the build step is missing.
esp-idf
...
-- App "hello_world" version: 1
-- Adding linker script /CustomBootloader/build/esp-idf/esp_system/ld/memory.ld
-- Adding linker script /opt/esp/idf/components/esp_system/ld/esp32c3/sections.ld.in
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.api.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.libgcc.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.newlib.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.version.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.eco3.ld
-- Adding linker script /opt/esp/idf/components/soc/esp32c3/ld/esp32c3.peripherals.ld
-- Components: app_trace app_update bootloader bootloader_support bt cmock console cxx driver efuse esp-tls esp_adc esp_app_format esp_common esp_eth esp_event esp_gdbstub esp_hid esp_http_client esp_http_server esp_https_ota esp_https_server esp_hw_support esp_lcd esp_local_ctrl esp_netif esp_phy esp_pm esp_psram esp_ringbuf esp_rom esp_serial_slave_link esp_system esp_timer esp_wifi espcoredump esptool_py fatfs freertos hal heap http_parser idf_test ieee802154 json log lwip main mbedtls mqtt newlib nvs_flash openthread partition_table protobuf-c protocomm pthread riscv sdmmc soc spi_flash spiffs tcp_transport tinyusb ulp unity usb vfs wear_levelling wifi_provisioning wpa_supplicant
-- Component paths: /opt/esp/idf/components/app_trace /opt/esp/idf/components/app_update /opt/esp/idf/components/bootloader /opt/esp/idf/components/bootloader_support /opt/esp/idf/components/bt /opt/esp/idf/components/cmock /opt/esp/idf/components/console /opt/esp/idf/components/cxx /opt/esp/idf/components/driver /opt/esp/idf/components/efuse /opt/esp/idf/components/esp-tls /opt/esp/idf/components/esp_adc /opt/esp/idf/components/esp_app_format /opt/esp/idf/components/esp_common /opt/esp/idf/components/esp_eth /opt/esp/idf/components/esp_event /opt/esp/idf/components/esp_gdbstub /opt/esp/idf/components/esp_hid /opt/esp/idf/components/esp_http_client /opt/esp/idf/components/esp_http_server /opt/esp/idf/components/esp_https_ota /opt/esp/idf/components/esp_https_server /opt/esp/idf/components/esp_hw_support /opt/esp/idf/components/esp_lcd /opt/esp/idf/components/esp_local_ctrl /opt/esp/idf/components/esp_netif /opt/esp/idf/components/esp_phy /opt/esp/idf/components/esp_pm /opt/esp/idf/components/esp_psram /opt/esp/idf/components/esp_ringbuf /opt/esp/idf/components/esp_rom /opt/esp/idf/components/esp_serial_slave_link /opt/esp/idf/components/esp_system /opt/esp/idf/components/esp_timer /opt/esp/idf/components/esp_wifi /opt/esp/idf/components/espcoredump /opt/esp/idf/components/esptool_py /opt/esp/idf/components/fatfs /opt/esp/idf/components/freertos /opt/esp/idf/components/hal /opt/esp/idf/components/heap /opt/esp/idf/components/http_parser /opt/esp/idf/components/idf_test /opt/esp/idf/components/ieee802154 /opt/esp/idf/components/json /opt/esp/idf/components/log /opt/esp/idf/components/lwip /CustomBootloader/main /opt/esp/idf/components/mbedtls /opt/esp/idf/components/mqtt /opt/esp/idf/components/newlib /opt/esp/idf/components/nvs_flash /opt/esp/idf/components/openthread /opt/esp/idf/components/partition_table /opt/esp/idf/components/protobuf-c /opt/esp/idf/components/protocomm /opt/esp/idf/components/pthread /opt/esp/idf/components/riscv /opt/esp/idf/components/sdmmc /opt/esp/idf/components/soc /opt/esp/idf/components/spi_flash /opt/esp/idf/components/spiffs /opt/esp/idf/components/tcp_transport /opt/esp/idf/components/tinyusb /opt/esp/idf/components/ulp /opt/esp/idf/components/unity /opt/esp/idf/components/usb /opt/esp/idf/components/vfs /opt/esp/idf/components/wear_levelling /opt/esp/idf/components/wifi_provisioning /opt/esp/idf/components/wpa_supplicant
-- Configuring done
-- Generating done
-- Build files have been written to: /CustomBootloader/build
...
[323/810] Performing configure step for 'bootloader'-- Found Git: /usr/bin/git (found version "2.25.1")
...
-- Adding linker script /opt/esp/idf/components/soc/esp32c3/ld/esp32c3.peripherals.ld
-- App "bootloader" version: v5.1-dev-1006-g02605f1a31
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.api.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.libgcc.ld
-- Adding linker script /opt/esp/idf/components/esp_rom/esp32c3/ld/esp32c3.rom.newlib.ld
-- Adding linker script /CustomBootloader/bootloader_components/esp-xz/ld/esp32c3/linker.lf
-- Adding linker script /opt/esp/idf/components/bootloader/subproject/main/ld/esp32c3/bootloader.ld
-- Adding linker script /opt/esp/idf/components/bootloader/subproject/main/ld/esp32c3/bootloader.rom.ld
-- Components: bootloader bootloader_custom_malloc bootloader_support efuse esp-xz esp_app_format esp_common esp_hw_support esp_rom esp_system esptool_py freertos hal log main micro-ecc newlib partition_table riscv soc spi_flash
-- Component paths: /opt/esp/idf/components/bootloader /CustomBootloader/bootloader_components/bootloader_custom_malloc /opt/esp/idf/components/bootloader_support /opt/esp/idf/components/efuse /CustomBootloader/bootloader_components/esp-xz /opt/esp/idf/components/esp_app_format /opt/esp/idf/components/esp_common /opt/esp/idf/components/esp_hw_support /opt/esp/idf/components/esp_rom /opt/esp/idf/components/esp_system /opt/esp/idf/components/esptool_py /opt/esp/idf/components/freertos /opt/esp/idf/components/hal /opt/esp/idf/components/log /CustomBootloader/bootloader_components/main /opt/esp/idf/components/bootloader/subproject/components/micro-ecc /opt/esp/idf/components/newlib /opt/esp/idf/components/partition_table /opt/esp/idf/components/riscv /opt/esp/idf/components/soc /opt/esp/idf/components/spi_flash
-- Configuring done
-- Generating done
-- Build files have been written to: /CustomBootloader/build/bootloader
...
pio
-- Component directory C:/Projects/app/bootloader_components/include does not contain a CMakeLists.txt file. No component will be added
-- Component directory C:/Projects/app/bootloader_components/tools does not contain a CMakeLists.txt file. No component will be added
-- Building ESP-IDF components for target esp32c3
-- Project sdkconfig file C:/Projects/app/sdkconfig.debug
-- App "app" version: cc5e6b0-dirty
-- Adding linker script C:/Projects/app/.pio/build/debug/esp-idf/esp_system/ld/memory.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_system/ld/esp32c3/sections.ld.in
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.api.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.libgcc.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.newlib.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.version.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.newlib-time.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.eco3.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/soc/esp32c3/ld/esp32c3.peripherals.ld
-- Components: __pio_env app_trace app_update asio bootloader bootloader_support bt cbor cmock coap console cxx driver efuse esp-tls esp32c3 esp_adc_cal esp_common esp_eth esp_event esp_gdbstub esp_hid esp_http_client esp_http_server esp_https_ota esp_https_server esp_hw_support esp_ipc esp_lcd esp_local_ctrl esp_netif esp_phy esp_pm esp_ringbuf esp_rom esp_serial_slave_link esp_system esp_timer esp_websocket_client esp_wifi espcoredump esptool_py expat fatfs freemodbus freertos hal heap idf_test ieee802154 jsmn json libsodium log
lwip mbedtls mdns mqtt newlib nghttp nvs_flash openssl openthread partition_table protobuf-c protocomm pthread riscv sdmmc soc spi_flash spiffs src tcp_transport tcpip_adapter tinyusb unity usb vfs wear_levelling wifi_provisioning wpa_supplicant
-- Component paths: C:/Projects/app/.pio/build/debug/__pio_env C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/app_trace C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/app_update C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/asio C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader_support C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bt C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/cbor C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/cmock C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/coap C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/console C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/cxx C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/driver C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/efuse C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp-tls C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp32c3 C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_adc_cal C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_common C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_eth C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_event C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_gdbstub C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_hid C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_http_client C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_http_server C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_https_ota C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_https_server C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_hw_support C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_ipc C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_lcd C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_local_ctrl C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_netif C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_phy C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_pm C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_ringbuf C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_serial_slave_link C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_system C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_timer C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_websocket_client C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_wifi C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/espcoredump C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esptool_py C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/expat C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/fatfs C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/freemodbus C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/freertos C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/hal C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/heap C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/idf_test C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/ieee802154 C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/jsmn C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/json C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/libsodium C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/log C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/lwip C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/mbedtls C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/mdns C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/mqtt C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/newlib C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/nghttp C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/nvs_flash C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/openssl C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/openthread C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/partition_table C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/protobuf-c C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/protocomm C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/pthread C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/riscv C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/sdmmc C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/soc C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/spi_flash C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/spiffs C:/Projects/app/src C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/tcp_transport C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/tcpip_adapter C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/tinyusb C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/unity C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/usb C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/vfs C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/wear_levelling C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/wifi_provisioning C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/wpa_supplicant
-- Configuring done
-- Generating done
-- Build files have been written to: C:/Projects/app/.pio/build/debug
-- Building ESP-IDF components for target esp32c3
-- Project sdkconfig file C:/Projects/app/sdkconfig.debug
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/soc/esp32c3/ld/esp32c3.peripherals.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.api.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.libgcc.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom/esp32c3/ld/esp32c3.rom.newlib.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader/subproject/main/ld/esp32c3/bootloader.ld
-- Adding linker script C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader/subproject/main/ld/esp32c3/bootloader.rom.ld
-- Components: bootloader bootloader_support efuse esp32c3 esp_common esp_hw_support esp_rom esp_system esptool_py freertos hal log main micro-ecc newlib partition_table riscv soc spi_flash
-- Component paths: C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader_support C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/efuse C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp32c3 C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_common C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_hw_support C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_rom C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esp_system C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/esptool_py C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/freertos C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/hal C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/log C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader/subproject/main C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/bootloader/subproject/components/micro-ecc C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/newlib C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/partition_table C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/riscv C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/soc C:/.platformio/packages/framework-espidf@src-10267632c96e5f6614e860958303d4f6/components/spi_flash
-- Configuring done
-- Generating done
-- Build files have been written to: C:/Projects/app/.pio/build/debug/bootloader
My configuration is shown below
[platformio]
src_dir = src
default_envs = debug
# Common build environment that is used for each of the tasks
[env]
board = esp32-c3-devkitm-1
platform = espressif32
framework = espidf
# 4 MB module version
board_upload.flash_size = 4MB
board_upload.maximum_size = 4194304
board_build.partitions = partitions.csv
board_build.filesystem = littlefs
board_build.embed_txtfiles =
# Settings for serial upload
upload_speed = 921600
upload_port = COM4
# Settings for serial console
monitor_speed = 115200
monitor_port = COM4
monitor_filters = esp32_exception_decoder
# Additional packages
platform_packages =
# Aditional build scripts for all environments to run before (`pre`) and after (`post`) the main build script
extra_scripts =
pre:scripts/Clean.py
# Common build flags for all environments
build_flags =
# Application version
-D APP_VERSION_MAJOR=0
-D APP_VERSION_MINOR=0
-D APP_VERSION_REV=1
# ESP32 specific
-D ESP32
lib_deps =
[env:debug]
build_type = debug
build_flags =
${env.build_flags}
-D DEBUG
lib_deps =
${env.lib_deps}
${env.lib_deps}
extra_scripts =
${env.extra_scripts}
[env:release]
build_type = release
build_flags =
${env.build_flags}
-D RELEASE
lib_deps =
${env.lib_deps}
${env.lib_deps}
extra_scripts =
${env.extra_scripts}
What is the correct way to build a custom bootloader with pio?