Tip

• SB2040 V3 comes pre-flashed with Katapult firmware for CAN connection at a rate of 1M
• SB2040 V3 Katapult firmware for CAN connection is available in 500K and 1M rates, you can flash it yourself if needed
• Katapult Firmware Flashing

Firmware Flashing Instructions

• SB2040 V3 can connect to the host via RS232 or CAN
• RS232 and CAN require an XT30(2+2)-F for connection
• Below is the appearance of the XT30(2+2)-F data cable
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Notice

• CAN firmware flashing requires flashing Klipper via Katapult (RS232 firmware uses USB direct flashing, no Katapult needed)
• If you are certain the mainboard already has Katapult flashed, you can skip the Katapult firmware flashing section at the end
• You can quickly press reset twice and check if an LED on the mainboard starts blinking; if so, it means the mainboard has entered Katapult firmware

Selecting the Firmware Type

Please confirm the connection method first.

• If a CAN toolboard is required: choose CAN firmware.
• If an RS232 connection is required: choose RS232 Firmware.
• Only one of the two firmware types can be selected. Do not flash both simultaneously.

Firmware Type	Applicable Scenario	Advantages	Confirm before selecting	Operation
CAN Firmware	When a CAN toolboard is required	Supports connecting multiple devices via CAN bus	Confirm the host supports CAN and prepare a UTOC or USB-CAN bridge mainboard	Compile CAN Firmware
RS232 Firmware	When an RS232 connection is required	Stable communication, simple configuration	Requires RS232 connection devices such as G2T or UTOR	Compile RS232 Firmware

Katapult Firmware Instructions

名称说明

Katapult 原名 CanBoot，两者在旧教程或旧固件名称中可能同时出现。

Katapult 是用于引导和更新 Klipper 的 Bootloader：

• Katapult 本身不能作为 Klipper MCU 使用，烧录后仍需写入与硬件和通信方式匹配的 Klipper 固件。
• 支持的工具板可以通过快速双击 RESET 按键进入 Katapult；进入后通常会有状态灯闪烁。
• CAN、RS232 和 USB 使用相互独立的 Katapult 固件，不能只修改文件名或直接混用。
• CAN 固件还必须选择正确的总线速率，常见速率为 500K 和 1M。