Troubleshooting DFU Mode Entry

I. Symptoms

When attempting to put the F405 WING flight controller into DFU mode for firmware flashing, you may encounter the following issues:

• After pressing the BOOT button and connecting the flight controller to the computer via USB, the INAV ground control station (GCS) fails to detect DFU mode.

• Device Manager shows "Unknown device" or STM32 BOOTLOADER is missing, preventing entry into DFU mode.

If you encounter the above situations, follow these steps to troubleshoot and install the correct DFU drivers.

II. Cause Analysis

Common causes preventing the F405 WING from entering DFU mode include:

1. USB Device Conflicts: When connecting the flight controller to the computer, it may be affected by other peripherals (GPS, VTX, receiver, etc.), preventing proper recognition of DFU mode.
2. Abnormal or Missing USB Drivers: If the flight controller is not properly recognized in Windows Device Manager, the STM32 drivers may not be installed or may be corrupted.
3. Incorrectly Installed Zadig Drivers: Some computers may not automatically recognize DFU mode when first connecting the F405 WING, requiring manual driver installation.
4. USB Cable or Port Issues: Poor quality or damaged USB data cables may prevent proper device recognition. It is recommended to use high-quality USB data cables.
5. Windows Security Policy Restrictions: Some Windows versions may block driver installation, requiring administrator privileges to run Zadig.

III. Solutions

3.1 Pre-installation Checks

Before installing drivers, please complete the following checks:

1. Disconnect all peripherals: Ensure that peripherals such as GPS, VTX, receiver, battery, etc. are all disconnected, and only connect the flight controller using a USB data cable**.

2. Verify DFU Recognition Status: Hold the BOOT button on the flight controller while inserting the USB cable and connecting to the computer. In 设备管理器, check if the STM32 BOOTLOADER device appears. If it does not appear, you need to manually install DFU drivers.

3.2 Zadig Driver Installation Steps

Step 1: Download Zadig Software

• Visit the Zadig official website: https://zadig.akeo.ie/
• Download the latest version of Zadig.exe and run it (recommended to run with administrator privileges).

Step 2: Connect the Flight Controller

1. Hold the BOOT button.

2. Use a USB data cable to connect the flight controller to the computer.

Step 3: Install DFU Driver

1. Open the Zadig software with administrator privileges.

2. In the menu bar, click Options and check the List All Devices option to ensure all devices are visible.

3. In the dropdown list, find STM32 BOOTLOADER (if it does not appear, please confirm the flight controller is properly connected).

4. Select the driver type WinUSB.

5. Click Reinstall Driver (Reinstall Driver) and wait for the driver installation to complete.

6. Driver installation successful.

IV. Result Verification

After completing driver installation, please follow these steps to confirm if DFU mode is available:

1. Disconnect the USB connection from the flight controller.

2. Hold the BOOT button again** and** only connect the flight controller to the computer using a USB data cable.

3. Open 设备管理器 and check if the STM32 BOOTLOADER device appears, and if the INAV ground control station (GCS) top-right corner displays DFU.

4. If DFU mode still does not activate, try:

• Replace the USB data cable.
• Reinstall drivers using Zadig.

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