CAN Firmware Compilation

Start Compilation

Brief Guide to Firmware Compilation

Notes

Network: Ensure the host (Raspberry Pi, etc.) is connected to the internet.
Login Method: Must log in via SSH over the network; serial port access is disabled.
Input Method: Keep the keyboard in English half-width mode.

Use tools like MobaXterm, PuTTY, etc., to SSH into the host.

Switch User:

Standard System (Official Raspberry Pi system, etc.)
Do not use root; switch to a regular user:
```
su <username>
```
FLY Host System (FlyOS-FAST system)
Only supports login as root user (password: mellow)

Firmware Compilation Operation Guide

In the Klipper firmware configuration interface, only keyboard operations are supported; the mouse cannot be used.

Key	Function
↑ / ↓	Move cursor up/down to select menu items
Enter / Space	Confirm selection, check options, or enter submenus
ESC	Return to the previous menu
Q	Exit the configuration interface
Y	If prompted when exiting, press Y to save the configuration

Start Firmware Compilation

The following describes how to compile the firmware:

After connecting via SSH, enter the following command and press Enter:

cd ~/klipper && rm -rf ~/klipper/.config && rm -rf ~/klipper/out && make menuconfig

Where rm -rf ~/klipper/.config && rm -rf ~/klipper/out is to delete previous compilation data and firmware
make menuconfig is for compiling the firmware, after execution you should see the following interface

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Select Enable extra low-level configuration options and press Enter

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Enter the menu Micro-controller Architecture then select Raspberry Pi RP2040/RP235x and press Enter

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Select Bootloader offset, select:16KiB bootloader

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Select Communication interface, select:CAN bus

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Select (4) CAN RX gpio number, delete 4 and input 1
Select (5) CAN TX gpio number, delete 5 and input 0

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Select GPIO pins to set at micro-controller startup, input: !gpio18
Caution
Please enter !gpio18 in English input mode

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Press the Q key, Save configuration will appear, then press the Y key

The configuration should now be saved and you will return to the command line interface
Enter the following command to start compiling, it will take some time

make -j4

The following output indicates successful compilation
Due to Klipper version issues, only the appearance of out/klipper.bin indicates success
```
Linking out/klipper.elf
Creating bin file out/klipper.bin
```

Flash Firmware

Before flashing the firmware, connect the tool board to a UTOC or a mainboard with bridge firmware using an XT30 data cable. Refer to the wiring diagram below.
Please check if the DIP switch is set to the correct position.

KF Interface Diagram

XT30 Interface Diagram

Ensure that the resistance between CAN H and CAN L, measured with a multimeter while powered off, is around 60Ω. If it is 120Ω, connect a 120Ω jumper. If it is around 40Ω, remove the jumper.
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Querying CANBus UUID

Notes Before Operation

It is recommended to perform ID queries and firmware flashing in a non-printing state to avoid interrupting the printing process.
The Katapult (CANBoot) firmware and Klipper firmware on the same motherboard/toolboard use the same CAN ID.

Prerequisites

Please ensure the following conditions are met; otherwise, it may not be possible to search for CAN IDs:

The host computer's CAN network is correctly configured
The CAN baud rate of the toolboard is exactly the same as that of the host computer (communication will fail if rates differ)
After executing the lsusb command, the 1d50:606f device (USB-CAN adapter) is visible

Search Command (Choose based on system)

Standard host machine search command

~/klippy-env/bin/python ~/klipper/scripts/canbus_query.py can0

FLY host machine search command

python3 ~/klipper/scripts/canbus_query.py can0

Explanation of Search Results

Scenario 1: Motherboard/Toolboard with Klipper Firmware Flashed

Display Effect: Shows one CAN ID, with the hint Application: Klipper
Explanation: The device is running Klipper firmware and can be used directly. This ID could belong to the motherboard or the toolboard.
Differentiation Method: Disconnect the toolboard's CAN connection cable and re-search. If this ID disappears, it belongs to the toolboard; if the ID remains, it belongs to the motherboard.

Scenario 2: Motherboard + Toolboard Ready for Flashing

Display Effect: Shows two CAN IDs
Explanation: The motherboard is running Klipper firmware, the toolboard is running CanBoot firmware and waiting to be flashed.

Scenario 3: UTOC + Toolboard Ready for Flashing

Display Effect: UTOC itself does not display an ID, only the toolboard's ID is shown
Explanation: UTOC acts only as a bridge. Ensure the toolboard is in CanBoot mode.

Scenario 4: No ID Displayed

Display Effect: No IDs are displayed
Possible Reasons:
1. CAN bus is occupied by Klipper
2. Incorrect baud rate configuration for the host's CAN0
3. Physical wiring issues
4. Device is not in CanBoot mode

Important Notes

Ready for Flashing State: When a toolboard is in CanBoot mode, it will show Application: CanBoot and its status LED will flash, indicating firmware can be flashed.
ID Occupied Handling: If a device is running Klipper firmware and its ID has been configured in the configuration file, the ID will not be displayed (occupied by Klipper). To make it visible again, comment out the ID in the configuration and perform a complete power cycle.

Troubleshooting

If the UUID cannot be queried, please refer to: CAN Troubleshooting Guide

Firmware Flashing

Flash Command

Replace 241696050c56 in the command below with your queried UUID
Note: Ensure there is a space after the -u parameter

Version Information

FlyOS-FAST 1.3.8 and above or systems with Klipper updated after April 9, 2026, use the new command:
```
python3 ~/klipper/lib/katapult/flashtool.py -u 241696050c56
```
Older systems (before FAST 1.3.8 or Klipper not updated before April 9, 2026), use the old command:
```
python3 ~/klipper/lib/canboot/flash_can.py -u 241696050c56
```

Flash Success Confirmation

Seeing the CAN Flash Success message indicates a successful flash:

Firmware Update

Update Method

When updating the firmware, simply:

Recompile the firmware
Ensure the device's CAN ID can be queried (or Klipper is connected to the device)
Execute the same flash command

Version Information

FlyOS-FAST 1.3.8 and above or systems with Klipper updated after April 9, 2026:
```
python3 ~/klipper/lib/katapult/flashtool.py -u <MCU ID>
```
Older systems (before FAST 1.3.8 or Klipper not updated before April 9, 2026):
```
python3 ~/klipper/lib/canboot/flash_can.py -u <MCU ID>
```

Update Success Example

Verify Firmware Startup

If the firmware starts normally, the LED will light up.
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Start Compilation​

Brief Guide to Firmware Compilation​

Notes​

SSH Login and User Switching​

Switch User:​

Firmware Compilation Operation Guide​

Start Firmware Compilation​

Flash Firmware​

KF Interface Diagram​

XT30 Interface Diagram​

Querying CANBus UUID​

Search Command (Choose based on system)​

Explanation of Search Results​

Scenario 1: Motherboard/Toolboard with Klipper Firmware Flashed​

Scenario 2: Motherboard + Toolboard Ready for Flashing​

Scenario 3: UTOC + Toolboard Ready for Flashing​

Scenario 4: No ID Displayed​

Firmware Flashing​

Flash Command​

Flash Success Confirmation​

Firmware Update​

Update Method​

Update Success Example​

Verify Firmware Startup​