Katapult (Bootloader) Firmware

Pre-flashed at Factory

The FLY-MMU is pre-flashed with Katapult at the factory. Do not re-flash the firmware on this page during normal use or when updating the Klipper firmware; this page is only for recovery after a bootloader corruption.

Firmware Description

Name Explanation

Katapult was formerly known as CanBoot, and both names may appear simultaneously in older tutorials or firmware names.

Katapult is a bootloader used to boot and update Klipper:

• Katapult itself cannot be used as a Klipper MCU; after flashing, you still need to write Klipper firmware that matches the hardware and communication method.
• Supported tool boards can enter Katapult by quickly double-pressing the RESET button; after entering, there is usually a status light blinking.
• CAN, RS232, and USB use independent Katapult firmware; you cannot simply modify file names or mix them directly.
• For CAN firmware, you must also select the correct bus speed, with common speeds being 500K and 1M.

• The FLY-MMU supports CAN, RS232, and USB communication.
• The repository provides USB firmware, as well as 500K and 1M CAN baud rate firmware.

Select Only One Firmware

USB and CAN firmware cannot be used simultaneously. When selecting a CAN firmware, the firmware baud rate must match the host and all CAN devices on the same bus.

Entering Flash Mode

Power Off Operation

Before starting, completely power off the printer and disconnect the power supply. Do not plug or unplug cables, arrange wiring, or touch terminals while the device is powered on.

In the figure, the top is the RESET button and the bottom is the BOOT button:

1. Keep the control board completely powered off.
2. Press and hold the BOOT button.
3. Connect the control board to a computer or host using a Type-C cable that supports data transfer.
4. Release the BOOT button once the device is recognized.

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Flashing Firmware

• Windows
• Linux / FLYOS

Download the FLY-MMU Katapult firmware:

• FLY_MMU_CANBOOT_USB.bin
• FLY_MMU_CANBOOT_CAN_500K.bin
• FLY_MMU_CANBOOT_CAN_1M.bin

Windows 默认可能隐藏文件扩展名。下载后请确认文件扩展名未被修改，不要保存成 .txt 或其他扩展名。

The firmware directory in the repository is:

FLY-Firmware/ToolBoard/MMU

• STM32CubeProgrammer
• DFU-AUTO

Power Off Operation

Before connecting or re-plugging the USB cable, completely shut down the printer and disconnect other power sources. Do not allow the tool board to be powered simultaneously via the printer's power supply and the USB interface.

USB Connection Compatibility

Some computer USB ports may cause unstable flashing due to driver or signal compatibility issues. If connection fails, try switching to a different USB port on the computer or use a reliable USB hub. If the error shown below appears, check the USB connection and drivers first.

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1. Download and install SetupSTM32CubeProgrammer and the STM32 DFU driver from the Auxiliary Software Download Page.
2. Save the firmware downloaded from this page to a location on your computer that is easy to find.

Windows File Extension Display

Windows may hide file extensions. Please check "File name extensions" in File Explorer to confirm the firmware is still in .bin or .hex format. Do not modify the file extension.

3. Confirm the device has entered DFU flashing mode according to the product tutorial, then connect it to the computer using a USB cable that supports data transfer.
4. Open STM32CubeProgrammer, select USB mode, refresh the device list, and connect.

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5. If no error popup appears, the connection is successful.

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6. Click the download icon on the left side, and check the flashing options as shown in the image below.

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7. Click Browse and select the firmware to be flashed.

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8. When flashing .bin firmware, set Start address to 0x08000000. When using .hex firmware, keep the address embedded in the file.

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9. Click Start automatic mode to begin flashing.

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10. When the success message appears, the firmware flashing is complete.

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Power Off Before Operation

Before connecting or reconnecting the USB cable, completely power off the printer and disconnect other power sources. Do not let the toolboard be powered simultaneously by both the printer power supply and the USB interface.

1. Download and run FLY DFU-AUTO.
2. If the "Driver Status" shows unavailable, click "Install Driver" to complete the WinUSB driver installation.
3. Click "Browse" to select the .bin firmware file to be flashed.

Windows File Extension Display

Windows may hide file extensions. In File Explorer, check "File name extensions" to confirm the firmware remains as .bin. Do not modify the file extension.

4. Click "Start Flashing", monitor progress through the run log, and wait for the flashing process to complete.

Detailed Tutorial: FLY DFU-AUTO Download and Usage

• Linux
• FLYOS

1. Install flashing tool.

   sudo apt update
   sudo apt install dfu-util -y

2. Confirm the device has entered DFU flashing mode.

   lsusb

   If you can see 0483:df11, it means DFU flashing mode has been entered successfully.

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3. Pull/update firmware repository.

   git clone https://cnb.cool/3dmellow/FLY-Firmware ~/FLY-Firmware
   cd ~/FLY-Firmware && git pull --ff-only

4. Flash firmware.

   FLY_MMU_CANBOOT_USB.bin

   sudo dfu-util -a 0 -d 0483:df11 --dfuse-address 0x08000000 -D ~/FLY-Firmware/ToolBoard/MMU/FLY_MMU_CANBOOT_USB.bin

   FLY_MMU_CANBOOT_CAN_500K.bin

   sudo dfu-util -a 0 -d 0483:df11 --dfuse-address 0x08000000 -D ~/FLY-Firmware/ToolBoard/MMU/FLY_MMU_CANBOOT_CAN_500K.bin

   FLY_MMU_CANBOOT_CAN_1M.bin

   sudo dfu-util -a 0 -d 0483:df11 --dfuse-address 0x08000000 -D ~/FLY-Firmware/ToolBoard/MMU/FLY_MMU_CANBOOT_CAN_1M.bin

5. If File downloaded successfully appears, flashing is successful.
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1. FLY host computer usually has dfu-util built-in, no need to install flashing tool again.
2. Confirm the device has entered DFU flashing mode.

   lsusb

   If you can see 0483:df11, it means DFU flashing mode has been entered successfully.

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3. Pull/update firmware repository.

   git clone https://cnb.cool/3dmellow/FLY-Firmware /data/FLY-Firmware
   ln -s /data/FLY-Firmware /root/FLY-Firmware
   cd /data/FLY-Firmware && git pull --ff-only

4. Flash firmware.

   FLY_MMU_CANBOOT_USB.bin

   sudo dfu-util -a 0 -d 0483:df11 --dfuse-address 0x08000000 -D /data/FLY-Firmware/ToolBoard/MMU/FLY_MMU_CANBOOT_USB.bin

   FLY_MMU_CANBOOT_CAN_500K.bin

   sudo dfu-util -a 0 -d 0483:df11 --dfuse-address 0x08000000 -D /data/FLY-Firmware/ToolBoard/MMU/FLY_MMU_CANBOOT_CAN_500K.bin

   FLY_MMU_CANBOOT_CAN_1M.bin

   sudo dfu-util -a 0 -d 0483:df11 --dfuse-address 0x08000000 -D /data/FLY-Firmware/ToolBoard/MMU/FLY_MMU_CANBOOT_CAN_1M.bin

5. If File downloaded successfully appears, flashing is successful.
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Completing the Flash

Power Off Operation

After flashing is complete, disconnect the control board USB and external power first, then restore normal wiring. Do not plug or unplug cables while the device is powered on.

After re-powering, the status LED will blink when Katapult is running normally:

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