Refactor v3.0.2

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The latest images for Recore and Replicape are available from github:

These instructions are for version v3.0.2 and older

ReFactor is the next generation of controller board software stack installation.

It is meant to simplify the lives of new users when they begin using a Thing-Printer controller board. Pre-built images of ReFactor are available for users who want to get up and running quickly with Replicape or Recore.

ReFactor is available for Replicape and Recore, with updates being propagated simultaneously for both platforms.

ReFactor uses Ansible as the underlying framework to describe the desired system state. There are many reasons for this:

  1. Ansible describes the system's end state, not individual actions to perform, so it is relatively easy to port across platforms (i.e. debian, arch, BSD...)
  2. The ReFactor repository can be updated from the git repository and Ansible will only change what has been updated from the previous version, not needing a complete reinstallation of the system for upgrades.
  3. Description of components is modular, making it easy to pick and choose different components for the end goal desired, while keeping each component's setup independent and reliable, and independently updatable.


The ultimate goal is to have multiple decliations of ReFactor, providing the user the ability to choose which firmware/software stack to run on their hardware. The following pre-build declinations are planned:

  • OctoPrint, Klipper, Replicape
  • OctoPrint, Klipper, Recore
  • OctoPrint, Klipper, Toggle, Replicape
  • OctoPrint, Klipper, Toggle, Recore
  • Duet Web Control, Klipper, Replicape
  • Duet Web Control, Klipper, Recore
  • OctoPrint, Klipper, Raspberry Pi [1-3]
  • OctoPrint, Klipper, Raspberry Pi 4 (arm64 edition)

Only the options in bold have been implemented so far, while the others are undergoing various steps in development in the order shown in this list. The ReFactor images with OctoPrint are meant to provide drop-in replacements for the previous Umikaze images, including all the extra goodies that were present in Umikaze, like mjpg-streamer, SMB server, and usbreset for the main ones.

The default login is root with password kamikaze. The system will prompt for an immediate password change, to prevent a massive IoT exploitation through the web. Wouldn't want your printer sending out spam or starting to print unauthorized objects, now would we?

So how do I use it?

ReFactor will be usable differently depending on what platform you're running it from.


The Replicape images will be meant to run from the micro SD you flash it to. You cannot boot the Replicape from a USB key at this time. By default, ReFactor images do not flash to the eMMC the way Umikaze used to. Part of this is historical - the early betas of ReFactor did not fit on the eMMC, but there's another advantage as well: it allows you to test out ReFactor on an SD card while keeping your working Redeem config on the eMMC.

Booting Refactor from USB

If you want to boot Refactor from a USB stick, you need to stop u-boot by pressing space during boot. You must run these commands:

setenv bootpart 0:1; setenv oldroot /dev/sda1; setenv devnum 0; run usb_boot

load ${devtype} ${bootpart} ${loadaddr} /boot/uEnv.txt; env import -t ${loadaddr} ${filesize}

run uname_boot


The Recore images will need to be flashed to a USB flash drive, as there is no SD slot on the board. Recore's uboot is designed to attempt to boot from a USB drive if there is no OS on the eMMC.

There are several stages to booting Recore, and depending on which media is installed, the boot process will try and boot either from eMMC, USB host or USB device.

Booting Recore from eMMC (the normal way)

  1. Turn on power
  2. The BROM will load u-boot SPL from eMMC
  3. The u-boot SPL will load u-boot
  4. u-boot will load Linux
  5. Linux will load the rootfs from eMMC.

Booting Recore from eMMC, but load rootfs from USB


Using a root file system on a different drive work well if the kernel version is the same on both media. The kernel version has changed between Refactor v3.0.2-RC3 and v3.0.2-RC4. The board will still boot, but will not load kernel modules as expected, including nft that maps OctoPrint to the HTTP port (80).

If the board is working normally and you are able to log in through ssh, but want to try out a new Refactor version you can let the rootfs be loaded from a USB drive (mass storage device):

  1. Download Refactor and flash it to a USB drive
  2. Insert the USB drive in the board.
  3. Boot the board normally
  4. Use SSH to log into the board: ssh root@recore.local
  5. Edit the commandline:
    1. nano /boot/armbianEnv.txt
    2. Add this line: extraargs=root=/dev/sda1
    3. Note: Starting from Refactor v3.0.2-RC4, the root partition is

number 2, so then instead use extraargs=root=/dev/sda2

  1. Reboot

The board should now be have the rootfs from the USB drive.

Booting Recore from USB, load Linux kernel from USB drive

This method requires a UART to USB adapter that can plug into a host computer. There is a 4 pin header on Recore marked DBG, where UART 0 is routed. All u-boot and kernel messages will appear here. If the eMMC is partitioned and has an OS, u-boot will launch right into that. In order to override that and load the boot script from a USB drive, stop u-boot by pressing a key and then write:

  1. Download Refactor and flash it to a USB drive
  2. Insert the USB drive in the board and apply power
  3. When the boot process gets to u-boot, you will see: Hit any key to stop autoboot:
  4. Hit the Any key.
  5. Then write run bootcmd_usb0

This will load the U-boot script from the USB drive and use the USB drive as the rootfs.

Boot Recore from a USB stick, eMMC is blank

Recore should come pre-flashed with Refactor image on the eMMC. If the eMMC has been wiped for some reason and you need to do everything from scratch, here are the instructions:

  1. Flash the ReFactor Linux distro to a USB drive.
  2. Insert the USB drive in the Recore board.
  3. Insert the Recore board in a host computer with the USB-C connector.
  4. If the eMMC is blank or the "FEL" button is pressed, the board will go into bootloader mode.
  5. Upload SPL, EL3 and u-boot through the USB port:
    1. Download the Recore repository
    2. Install the sunxi-tools program
    3. Run make fel
  6. The board will boot using the USB drive.
  7. Copy the contents of the USB drive into the eMMC/Internal flash.

You can read more about the steps needed to boot aboard in FEL mode on the Sunxi wiki:

AR100 firmware

The ar100 has a binary file that is loaded on startup by klipper.service The binary file comes pre-compiled in Refactor, but can be recompiled on Recore (or on a host computer).

Cross compilation toolchain for ARM64

The AR100 needs a cross compilation toolchain. For ARM64, it can be downloaded from

The toolchain has been built with

GCC version: 9.2.0

Cross compilation toolchain for x86_64

The toolchain used during automatic testing and is the same used for the CRUST firmware project:

Compiling the ar100 binary

cd /opt
tar xf or1k-linux-musl.tar.xz
export PATH=$PATH:/opt/output/bin

To configure klipper for AR100 and build the binary:

cd /home/debian/klipper/
cp test/configs/ar100.config .config
make olddefconfig

This will produce a bin file located in out/ar100.bin, so it should be moved to /op/firmware

mv out/ar100.bin /opt/firmware/

This is the same operation that happens from the klipper.service script, so it can also be done by running

systemctl restart klipper

STM32 firmware


The latest Refactor now does automatic flashing of the STM32 firmware on first boot after a fresh install. This was merged with PR#199 in Refactor on Github.

The firmware for the stm32f031 mcu that is responsible for ADC conversions and PWM for heaters and fans comes pre-installed in the flash of the MCU. It can be recreated on the board using the Klipper build system.

cd /home/debian/klipper
cp test/configs/stm32f031.config .config
make menuconfig
-> Enable extra low-level configuration options
-> Clock Reference internal
-> Communication interface (Serial (on USART2 PA15/PA14))
-> Baud rate for serial port: 38400

Flashing STM32 firmware

To flash the STM32 firmware:

systemctl stop klipper
make recoreflash FLASH_DEVICE=/dev/ttyS4
systemctl start klipper

Flashing ReFactor from a USB drive

Get the latest ReFactor image from here: for example:


Assuming you have managed to boot Recore from a USB flash drive and you have the ReFactor image available in the same folder, you can use dd to do a direct transfer of the image from the USB drive to eMMC. On Replicape / BeagleBone this will be /dev/mmcblk1

xz -v -d -c Refactor-recore-v3.0.0-2021-08-06.img.xz  | dd of=/dev/mmcblk0

Upgrading Refactor from the command line

Refactor has been set up using Ansible, so it should be possible to use the same setup to update Refactor after it has been installed.


cd /usr/src/
git clone
cd Refactor

Running Klipper

While details are ironed out there is a script that can be used to restart Klipper that will handle resetting things and setting up the steppers etc.

systemctl restart klipper

Running OctoPrint

OctoPrint should start and run on boot, but if there is a need to restart the daemon, use this command

systemctl restart octoprint

Update u-boot on Recore

Place u-boot-sunxi-with-spl.bin in sector 15 (8KB offset) Clean 1M of the eMMC:

dd if=/dev/zero of=/dev/mmcblk0 bs=1k count=1023 seek=1

Flash the binary

dd if=u-boot-sunxi-with-spl.bin of=/dev/mmcblk0 bs=1024 seek=8 conv=notrunc

Note: U-boot needs to be patched in order to use the eMMC as the first (and only) boot device. The changes can be done in "spl_mmc_get_device_index" where dev_num should be 0 instead of 1.

Building a runnable image for Replicape

The Replicape runs on a Beaglebone black (or green, without video output), which has a single core ARM processor running at 1GHz with 512MB of RAM. While impressive for an embedded application, it's rather weak when trying to build a system, which can take a lot of time.

There's a significant time gain when building the image from a more powerful host system, then flashing it to memory from an SD card.

The host system can be any ARM v7 or above architecture machine. In this example, the Raspberry Pi 4 will be used as an example, as it has a quad-core arm64 1.5GHz processor with 1 to 4GB of RAM. Any standard linux platform will do, but you will need a build storage space of at least 5GB for the build to succeed. Using a fast SD or a USB3 flash drive can provide higher disk speeds, reducing build time significantly.

To build an image from ReFactor for the Replicape, follow these steps:

  1. Browse to a folder on the pi where you wish to run the build
  2. Clone the git repository for ReFactor
  3. In the ReFactor folder, run the script. It may take some time, so you may want to consider using a screen or byobu session to protect against network drops if you're doing so through SSH.
  4. If the build completes successfully, you should be left with a file 'Umikaze-console.img.xz'
  5. Use etcher to write the .img.xz file to a micro SD card, insert it into the Beaglebone, power it up and wait for it to power down.
  6. Start using the ReFactor image on your printer

Installing a custom software stack with ReFactor from a base Debian image

At the moment ReFactor only supports using a debian-based distribution as a basis. Further down the line it will be refactored so that many more packaging systems are supported - this is not an Ansible limitation, but rather simply a developer time limitation.

The goal for ReFactor is to allow the end-user to choose a custom software stack, while making installation of those packages easier. In this case, the user will want to learn how to write a simple Ansible playbook - there are multiple examples available in the ReFactor base folder (build_full_klipper_octoprint.yml, install_klipper.yml, any yml file really).

The files starting with "build_full_" are meant to be used for the image building described in the previous section. The files starting with "install_" are designed to be run on a printer platform exclusively - not on a host system.

Each install_ file will install a specific component with its required dependencies. For instance, if you with install toggle, it will also install the Beaglebone's graphics drivers, required for video output, along with a number of libraries that Toggle is reliant on (such as a custom-built libclutter using the framebuffer output instead of the X11 driver).

To install a specific component, make sure that you have installed ansible. Alternatively you can just run the script - the only thing it does is make sure that Ansible is ready to execute any further tasks required.

Once Ansible is installed, just run "ansible-playbook install_klipper.yml" for example. Let it run and it will go through to make sure everything is available upon the next reboot.

After all packages have been installed as desired, reboot the system. A reboot is necessary, as depending on the software installed, kernel modules may be enabled / disabled, kernel versions may have changed etc. These are unfortunately not changes that can be done without a reboot.