# Bootloader TinyUF2 Example UF2 is a file format developed by Microsoft for [PXT](https://github.com/Microsoft/pxt). It is particularly suitable for flashing microcontrollers through Mass Storage Class devices. For a more accessible explanation, check out [this blog post](https://makecode.com/blog/one-chip-to-flash-them-all). ## How to Use ### Build and Flash Run `idf.py build` to compile the example. (To exit the serial monitor, press Ctrl-]) Refer to the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for detailed steps on configuring and using ESP-IDF to build projects. ### Drag and Drop for Upgrades * Build and flash the initial firmware with Bootloader TinyUF2 support. * By pulling the `CONFIG_BOOTLOADER_UF2_GPIO_NUM` pin to `CONFIG_BOOTLOADER_UF2_GPIO_LEVEL` for `CONFIG_BOOTLOADER_UF2_GPIO_PULL_TIME_SECONDS` seconds, the device will enter TinyUF2 mode. * In TinyUF2 mode, the indicator LED connected to `BOOTLOADER_UF2_LED_INDICATOR_GPIO_NUM` will start blinking. * Plug the `ESP32S3` into a computer via USB, and a new disk named `ESP32S3 - UF2` will appear in the file manager. * Run `idf.py uf2-ota` to generate or convert subsequent firmware upgrade files into UF2 format. For more details, see [esp_tinyuf2](../../../../components/usb/esp_tinyuf2/). * Drag and drop the UF2 firmware onto the disk to perform the upgrade. * After the upgrade, the device will automatically restart and boot from the `Factory` partition.  ### Modify NVS Configurations via `INI` File Preparation: * Build and flash the initial firmware with Bootloader TinyUF2 support. * By pulling the `CONFIG_BOOTLOADER_UF2_GPIO_NUM` pin to `CONFIG_BOOTLOADER_UF2_GPIO_LEVEL` for `CONFIG_BOOTLOADER_UF2_GPIO_PULL_TIME_SECONDS` seconds, the device will enter TinyUF2 mode. * Plug the `ESP32S3` into a computer via USB, and a new disk named `ESP32S3 - UF2` will appear in the file manager. * Open the `CONFIG.INI` file, modify the configurations, and save the file. * The saved file will be automatically parsed, and the new key-value pairs will be written to NVS. ### Known Issues The following error message may appear: ``` uf2: No such namespace entry was found ``` - This occurs because the namespace `CONFIG_BOOTLOADER_UF2_NVS_NAMESPACE_NAME` (uf2_nvs) does not yet exist in the NVS partition. It does not affect normal functionality. ### Additional Documentation [bootloader_uf2](https://docs.espressif.com/projects/esp-iot-solution/en/latest/usb/usb_device/esp_tinyuf2.html) ### Example Output ``` I (8456) esp_image: segment 0: paddr=00010020 vaddr=3f000020 size=0857ch ( 34172) map I (8466) esp_image: segment 1: paddr=000185a4 vaddr=3ffbd8c0 size=01d98h ( 7576) I (8466) esp_image: segment 2: paddr=0001a344 vaddr=40022000 size=05cd4h ( 23764) I (8476) esp_image: segment 3: paddr=00020020 vaddr=40080020 size=18248h ( 98888) map I (8496) esp_image: segment 4: paddr=00038270 vaddr=40027cd4 size=05be4h ( 23524) I (8506) esp_image: segment 5: paddr=0003de5c vaddr=50000000 size=00010h ( 16) I (8556) uf2_example: Firmware update complete I (8556) uf2_example: Restarting in 5 seconds... I (9556) uf2_example: Restarting in 4 seconds... I (10556) uf2_example: Restarting in 3 seconds... I (11556) uf2_example: Restarting in 2 seconds... I (12556) uf2_example: Restarting in 1 seconds... I (13556) uf2_example: Restarting in 0 seconds... I (14556) uf2_example: Restarting now ```
To create a project from this example, run:
idf.py create-project-from-example "espressif/esp_tinyuf2=1.1.0:bootloader_uf2"