@sheepdog said in flash m5stack fisheyes camera ov2640: Which esp-idf version did you use? You can get the Version with: $ git describe In the begining with esp-idf v4.2 And with esp-idf 3.3 realease can't finish "build" Adding ESP-IDF tools to PATH... Not using an unsupported version of tool xtensa-esp32-elf found in PATH: esp-2020r1-8.2.0. Not using an unsupported version of tool cmake found in PATH: 3.16.4. Not using an unsupported version of tool openocd-esp32 found in PATH: v0.10.0-esp32-20200406. Not using an unsupported version of tool ninja found in PATH: 1.10.0. C:\Users\oxyrace.espressif\tools\xtensa-esp32-elf\1.22.0-80-g6c4433a5-5.2.0\xtensa-esp32-elf\bin C:\Users\oxyrace.espressif\tools\esp32ulp-elf\2.28.51.20170517\esp32ulp-elf-binutils\bin C:\Users\oxyrace.espressif\tools\cmake\3.13.4\bin C:\Users\oxyrace.espressif\tools\openocd-esp32\v0.10.0-esp32-20190313\openocd-esp32\bin C:\Users\oxyrace.espressif\tools\mconf\v4.6.0.0-idf-20190628 C:\Users\oxyrace.espressif\tools\ninja\1.9.0 C:\Users\oxyrace.espressif\tools\idf-exe\1.0.1 C:\Users\oxyrace.espressif\tools\ccache\3.7 C:\Users\oxyrace.espressif\python_env\idf3.3_py3.8_env\Scripts [836/837] Linking CXX executable camera.elf FAILED: camera.elf cmd.exe /C "cd . && C:\Users\oxyrace.espressif\tools\xtensa-esp32-elf\1.22.0-80-g6c4433a5-5.2.0\xtensa-esp32-elf\bin\xtensa-esp32-elf-g++.exe -mlongcalls -nostdlib @CMakeFiles\camera.elf.rsp -o camera.elf && cd ." esp-idf/main/libmain.a(main.c.obj):(.literal.app_main+0x18): undefined reference to led_brightness' esp-idf/main/libmain.a(main.c.obj): In functionapp_main': D:\ESP32\esp-idf\examples\m5stack\wifi\wifi_sta\build/../main/main.c:89: undefined reference to `led_brightness' collect2.exe: error: ld returned 1 exit status ninja: build stopped: subcommand failed. ninja failed with exit code 1