Bootloader aware Klipper MCU

Hi everyone,

Are there some Ideas how to make Klipper bootloader aware? So the MCU could be send into Bootloader mode with a command from the Host device and than flashed without ever touching hardware in the System.

I’m currently working on a multi MCU system, all connected by an CANbus.
My MCU-Boards only use CAN to communicate, no UART or USB. Currently I have to remove every Board and connect it to an ST-Link programmer to flash a new firmware version.

I’m thinking about a custom bootloader that could flash via CAN. Similar to this first anwser

Thanks, Klipper is AWESOME!

I’ve done some more research and experimentation.

And did come up with a proof of concept that works for my system using CANbus, using this bootloader cvra can-bootloader with some custom adjustments to support my stm32F103 platform.
This is a 12k bootloader so I added an option to the klipper Kconfig file.

The bootloader waits 10s before starting application code. In this timeframe, I can now flash my Board over CAN (can-bootloader contains a flash client tool), but this works only 10s after a restart.

The next step for me was to make klipper firmware aware how to set the MCU into bootloader mode without timeout.

I added bootloader mcu command to klipper firmware that loads a magic+argument value into the beginning of the RAM and resets the MCU. This tells the bootloader to stay.
I also added a bootloader extra to klippy to enable this comand for a given MCU.

This is just a proof of concept for my project. This is my first time developing a part of klipper, advice is very welcome.

Are there similar bootloaders out there, that we could include?
How could this be integrated into klipper?

My Code:
can-bootloader platform can-3d-tool
my klipper changes (, stm32f103.c, stm32/Kconfig)

Example Usage

To build the Bootloader you have to also load the submodules.

 git submodule update --init --recursive

and change the platform.c for your needs (CAN Pins and Oscillator settings)

Then follow the steps for build in the readme.markdown

Example klipper config for using can-bootloader

# This enables the BOOTLOADER MCU=mcu GCode to send the main mcu into can-bootloader without timeout
[bootloader mcu]

[mcu my_ctl2]

# This enables the BOOTLOADER MCU=my_ctl2 GCode to send the mcu:my_ctl2 into can-bootloader without timeout
[bootloader my_ctl2]

Also see the can-bootloader/client readme to see how to send commands/firmware to the bootloader over CAN

Interesting. I can say there is interest in a CAN bootloader. I’m also aware that @Arksine put together a prototype for one - GitHub - Arksine/CanBoot: Can Bootloader for Klipper MCUs .

There has also been some background discussions for a mechanism to enter the bootloader from Klipper. What was previously discussed was adding a CANbus command (as in to instruct Klipper to reboot into the bootloader. (The reason using a CANbus command vs a normal Klipper command was discussed was to make it easier for an external script to trigger the bootloader.)


1 Like

@revilo196 as Kevin has posted, Katapult bootloader (formerly known as CanBoot) does this already. Kevin has aided in a lot of the code for Katapult.

Katapult can update itself and Klipper via the CAN bus, UART, or USB via it’s make menuconfig.

Do you think, I mean:


Oops, it just popped up as a new conversation on mine.


No worries.

I close it then.