Tip

• MMU provides Katapult firmware for USB and CAN connections, which can be flashed as needed
• MMU is pre-flashed with Katapult firmware for CAN connection at a rate of 1M
• Katapult Firmware Flashing

Firmware Flashing Instructions

• MMU can connect to the host via three connection methods: RS232, CAN, and USB
• RS232 and CAN require an XT30(2+2)-F cable for connection, while USB requires a TYPE-C data cable with data transfer capability
• Below is the appearance of the XT30(2+2)-F data cable
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Notice

• CAN and USB firmware flashing requires flashing Klipper through Katapult (RS232 firmware is flashed directly using DFU mode, no Katapult needed)
• If you are certain that the mainboard has already been flashed with Katapult, there is no need to perform the Katapult firmware flashing 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 needed: select CAN firmware.
• If an RS232 connection is needed: select RS232 Firmware.
• If a CAN toolboard is not used and a direct USB connection is needed: select USB firmware.
• Only one of the three firmware types can be selected; do not flash multiple types simultaneously.

Firmware Type	Applicable Scenario	Advantage	Confirm Before Selecting	Operation
CAN Firmware	When a CAN toolboard is needed	Supports multiple devices on the CAN bus	Confirm the host supports CAN and prepare a UTOC or USB-CAN bridge board	Compile CAN Firmware
RS232 Firmware	When an RS232 connection is needed	Stable communication, simple configuration	Requires an RS232 connection device such as G2T or UTOR	Compile RS232 Firmware
USB Firmware	When a direct USB connection is needed	Stable communication, simple configuration	Confirm that the host's USB port and data cable communicate properly	Compile USB 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。