Where do I find bootloader.bin?

mahboudz · October 27, 2022, 8:36am

HI. I’ve got a program that I upload to my ESP32 using VSCode and PIO and it works great.

I wanted to send the firmware.bin to someone to have them use the ESP32 Downloader to burn to their ESP32. They said they needed the partitions.bin and the bootloader.bin. The partitions.bin file I can find, but I don’t see where the bootloader.bin file is. Can you please direct me? Thanks!!

maxgerhardt · October 27, 2022, 8:54am

As you can see in

github.com

espressif/arduino-esp32/blob/2.0.5/tools/platformio-build.py#L71-L94


      
          def get_bootloader_image(variants_dir):
              bootloader_image_file = "bootloader.bin"
              if partitions_name.endswith("tinyuf2.csv"):
                  bootloader_image_file = "bootloader-tinyuf2.bin"
          
          
    variant_bootloader = join(
                  variants_dir,
                  board_config.get("build.variant", ""),
                  board_config.get("build.arduino.custom_bootloader", bootloader_image_file),
              )
          
          
    return (
                  variant_bootloader
                  if isfile(variant_bootloader)
                  else join(
                      FRAMEWORK_DIR,
                      "tools",
                      "sdk",
                      build_mcu,
                      "bin",

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PlatformIO will choose the bootloader file for ESP32 from one of the files in arduino-esp32/tools/sdk/esp32/bin at 2.0.5 · espressif/arduino-esp32 · GitHub. Since this includes the flash mode and flash frequency (e.g., DIO + 40MHz), this has to match the type of ESP32 module that the firmware is run on. Else the firmware will not boot at all.