Katapult (Bootloader) Firmware

Pre-flashed at the Factory

The FLY-SHT36 LIS3DH comes pre-flashed with Katapult from the factory. Do not re-flash the firmware on this page during normal use or when updating the Klipper firmware. This page is intended solely 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-SHT36 LIS3DH uses CAN communication.
• This page provides Katapult firmware for 500K and 1M CAN bus rates.

CAN Rate Must Match

Select only one firmware that matches the actual CAN network rate. The host, the mainboard, and all CAN devices on the same bus must use the same rate.

Entering Flash Mode

Power Off Before Operation

Before starting, completely turn off the printer and disconnect the power supply. Do not plug or unplug wiring harnesses, organize interface wiring, or touch terminals while the system is powered on.

The BOOT pad is indicated in the image below:

1. Keep the toolboard completely powered off.
2. Use a jumper cap to short the BOOT pad.
3. Connect the toolboard to a computer or host using a Type-C cable that supports data transfer.
4. Remove the BOOT jumper cap once the device is recognized.

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Flashing the Firmware

• Windows
• Linux / FLYOS

Download the FLY-SHT36 LIS3DH Katapult firmware:

• FLY_SHT36LIS3DH_CANBOOT_CAN_500K.uf2
• FLY_SHT36LIS3DH_CANBOOT_CAN_1M.uf2

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 directory of the firmware in the repository is:

FLY-Firmware/ToolBoard/SHT36

1. Confirm that the tool board has entered UF2 flashing mode, and a removable disk named RPI-RP2 appears on your computer.

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2. Release the BOOT button or remove the BOOT jumper.

Windows File Extension Display

Windows may hide file extensions. Please check "File name extensions" in File Explorer and ensure you are using the .uf2 firmware; do not modify the firmware file extension.

3. Copy the .uf2 firmware to be flashed to the RPI-RP2 disk.

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4. After the firmware write is complete, the RPI-RP2 disk will automatically disappear, indicating that the UF2 firmware has been successfully flashed.

1. Compile the RP2040 flashing tool. You can skip this step if it has already been done.

cd ~/klipper/lib/rp2040_flash/
make

2. Confirm that the toolboard has entered UF2 flashing mode.

lsusb

If 2e8a:0003 appears in the output, it indicates that the device has entered RP2040 flashing mode. The device name displayed may vary across different systems, so the USB ID should be used as the reference.

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Device Not Detected

Do not proceed with flashing if 2e8a:0003 does not appear. Please disconnect the toolboard power and repeat the steps in the "Entering Flashing Mode" section on this page.

3. Pull or update the precompiled firmware repository.

• Linux
• FLYOS

First-time download:

cd ~
git clone https://cnb.cool/3dmellow/FLY-Firmware.git

Update the repository if it has already been downloaded:

git -C ~/FLY-Firmware pull --ff-only

First-time download:

git clone https://cnb.cool/3dmellow/FLY-Firmware.git /data/FLY-Firmware
ln -s /data/FLY-Firmware /root/FLY-Firmware

Update the repository if it has already been downloaded:

git -C /data/FLY-Firmware pull --ff-only

4. Based on the CAN rate, execute only one of the following flashing commands:

CAN 500K:

sudo ~/klipper/lib/rp2040_flash/rp2040_flash ~/FLY-Firmware/ToolBoard/SHT36/FLY_SHT36LIS3DH_CANBOOT_CAN_500K.uf2

CAN 1M:

sudo ~/klipper/lib/rp2040_flash/rp2040_flash ~/FLY-Firmware/ToolBoard/SHT36/FLY_SHT36LIS3DH_CANBOOT_CAN_1M.uf2

5. Only power off after the successful flashing prompt appears.

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Completing the Flash

Power Off Before Operation

After flashing is complete, first disconnect the toolboard's USB and external power, then restore normal wiring. Do not plug or unplug the toolboard wiring harness while powered on.

After powering on again, the status LED will blink when Katapult starts normally:

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