M3-CRETE Software Setup

On your computer, download and install Raspberry Pi Imager from raspberrypi.com/software. It is the tool that writes the operating system to the card.

Put the microSD card into your computer. Open Raspberry Pi Imager and:

• Choose Device: Raspberry Pi 5.
• Choose OS: scroll to Other specific-purpose OS → 3D printing → MainsailOS, and pick the 64-bit version. (If you do not see it, download the MainsailOS file from docs.mainsail.xyz and use Use custom.)
• Choose Storage: your microSD card.

Before writing, click the gear / edit settings button. This part saves a lot of trouble later. Set:

• Hostname: m3crete (this becomes the web address).
• Enable SSH and set a username and password. (SSH is a way to type commands into the Pi from your computer. Write the username and password down.)
• Wi-Fi: your network name and password.
• Country / time zone: your own.

Then click Write. Wait for it to finish. This takes several minutes.

Put the microSD card into the Raspberry Pi. Connect the touchscreen if you have one. Power on the Pi. The first start takes a few minutes while it sets itself up.

On your phone or computer (on the same Wi-Fi), open a browser and go to:

http://m3crete.local/

You should see the Mainsail dashboard. It will show an error like "Klipper not ready" — that is normal for now. We fix it in the next parts.

On your computer, open a terminal (on Windows, use "PowerShell" or "Windows Terminal"). Type this, using the username you chose, then press Enter and type your password:

ssh [email protected]

You are now "inside" the Pi. The commands below are typed here.

Type these two lines, one at a time:

cd ~/klipper
make menuconfig

A blue menu opens. Use the arrow keys and Enter to set these options (leave everything else as it is):

• Micro-controller Architecture → STMicroelectronics STM32
• Processor model → STM32H723
• Bootloader offset → 128KiB bootloader
• Clock Reference → 25 MHz crystal
• Communication interface → USB (on PA11/PA12)

Press Q to quit the menu, then Y to save. Now build it:

make

When it finishes, the new firmware file is at ~/klipper/out/klipper.bin.

• Take the Kraken's microSD card out and put it in your computer. Make sure it is formatted FAT32 and is empty.
• Copy klipper.bin onto the card and rename it exactly to firmware.bin.
• Put the card back in the Kraken. Turn the board off, then on. Wait about 15–30 seconds — the board flashes itself.

Plug the USB cable from the Kraken into the Raspberry Pi. Make sure the board has its own power (the logic power, not the big motor supply yet).

Back in the SSH window (inside the Pi), type these lines one at a time:

cd ~
git clone https://github.com/sunnyday-technologies/M3-CRETE-FIRMWARE.git
cd M3-CRETE-FIRMWARE
bash install.sh

The installer will:

• Put the M3-CRETE config into place (it backs up any old one first).
• Install KlipperScreen for the touchscreen.
• Find your Kraken board automatically and fill in its address.
• Restart everything.

If you do not want the touchscreen app, run bash install.sh --no-screen instead.

Go back to Mainsail in your browser (http://m3crete.local/) and refresh the page. At the top it should now say Klipper: Ready. That means the Pi and the board are talking. 🎉

In Mainsail, find the Console (the box where you can type commands). Type:

ZHOLD

All four Z motors should now "hold" — try to turn one by hand and it should resist. To let them go free again, type ZRELEASE.

Type these, one at a time. Each one nudges a single motor a small amount:

ZJOG MOTOR=0 DIST=5 VEL=3
ZJOG MOTOR=1 DIST=5 VEL=3
ZJOG MOTOR=2 DIST=5 VEL=3
ZJOG MOTOR=3 DIST=5 VEL=3

Watch each motor. You want to see two things:

• It moves. If a motor does nothing, check its wiring and that its driver slot is correct.
• It moves the right way. A positive number (DIST=5) should raise that corner. If a corner goes down instead, that motor's direction needs to be flipped — note it down for Part 4.

To send a corner back down, use a negative number, like ZJOG MOTOR=0 DIST=-5 VEL=3.