How to Set Up a Duet 3 6HC SD Card and Troubleshoot Startup Issues

If your Duet 3 6HC is not starting from the SD card, follow this guide to properly set up the SD card and troubleshoot any issues.

1. Format the SD Card Properly

• Use a fresh SD card, preferably 8GB or 16GB (avoid very large sizes like 128GB).
• Format it as FAT32 (not exFAT).
  • Windows: Use the built-in formatter or Rufus.
  • Linux/Mac: Use gparted or diskutil.

2. Copy Files to the SD Card

1. Download the required files: duet3_full_sd_card.zip
2. Extract the contents to the root of the SD card (not inside another folder).
   The folder structure should look like this:

   /sys/
   /gcodes/
   /macros/
   /www/
   /firmware/
   /menu/
   

3. Verify that config.g is inside the /sys/ folder.

3. Insert the SD Card & Power On

1. Insert the SD card into the Duet 3 6HC SD card slot.
2. Power the Duet 3 via VIN power (recommended) or USB.
3. If the board does not start, check the Diag LED status:
   • LED On Constantly: The board is not reading the SD card.
   • LED Blinking: The firmware is booting correctly.

4. Check Duet 3 Connection via USB

If the board isn’t responding:

1. Connect a USB cable to your PC.
2. Open a serial terminal (e.g., YAT on Windows, screen on Linux/Mac):
   • Windows: Use YAT, set baud rate to 115200, and connect to the COM port.
   • Linux/Mac: Open a terminal and type:

     ls /dev/ttyUSB*
     screen /dev/ttyUSB0 115200
     

3. Send the command:

   M115
   

   This should return the firmware version.

5. Flash Duet 3 Firmware (If Needed)

A. Manually Load Firmware (If Board Doesn’t Boot)

1. Download the latest Duet3Firmware.bin from Duet3D GitHub.
2. Copy Duet3Firmware.bin to the /firmware/ folder on the SD card.
3. Reinsert the SD card and power cycle the board.

B. Flash Firmware via USB

If the SD card method doesn’t work, manually flash via USB:

1. Download BOSSA (for flashing Duet firmware):
   • Windows
   • Linux/Mac: Install via:

     sudo apt install bossa-cli  # Ubuntu/Debian
     brew install bossac         # macOS
     

2. Put the Duet into "bootloader mode":
   • Press and hold the "Erase" button.
   • While holding it, press and release the "Reset" button.
   • Release "Erase" after 2-3 seconds.
3. Flash the firmware using BOSSA:

   bossac -e -w -v -b Duet3Firmware.bin
   

4. Restart the Duet.

6. Verify Network Connectivity (If Using SBC Mode)

• If the Duet 3 was previously in SBC mode (with a Raspberry Pi), it may expect the Pi.
• To use Standalone mode, ensure:
  • The config.g file contains:

    M552 S1  ; Enable networking
    

  • The /www/ folder has Duet Web Control files.

7. Last Resort: Test Another SD Card

• Some SD cards are not compatible with the Duet 3.
• Try using a SanDisk Ultra (8GB-32GB).
• If possible, test with another Duet 3 board to rule out hardware issues.

Conclusion

1. Ensure the SD card is formatted correctly and files are in the right place.
2. Verify via USB that the board is detected.
3. Check the firmware and reflash if necessary.
4. If using standalone mode, enable networking in config.g.

By following these steps, your Duet 3 6HC should be up and running. Let us know in the comments if you have any issues!