Connecting an SKR3EZ H723 via SBC | RepRapFirmware for LPC and STM32

How to connect to an SKR3EZ H723 via SBC

Important: This USB connection method is only supported from RRF 3.7 beta 1 onwards. Do not use it with an earlier version of RRF. This method will become our preferred way to set up SBC mode in the future.

Prepare the SBC

Before you connect the SKR3EZ H723 to the SBC, complete step 1 and step 2 of the official Duet3D SBC setup guide.

Warning: If DSF (Duet Software Framework) is already installed on your SBC, you must first update to the latest Trixie-based build released by Duet3D. Trixie is the codename for Debian 13, the operating system that the latest DuetPi images are based on. Older, non-Trixie builds are not supported.

Next, download the RRF upgrade script onto the SBC. Connect to the SBC using SSH or a console connection, then run the following command. You only need to run this command once.

sudo wget https://raw.githubusercontent.com/TeamGloomy/rrf_stm32_sbc/master/armbian/userpatches/overlay/rrf_upgrade.sh -O /usr/local/bin/rrf_upgrade && sudo chmod a+x /usr/local/bin/rrf_upgrade

Now use the script to install the firmware build you want, and set the communication method to USB at the same time. Run the following command. Replace <version> with the build you want to install.

rrf_upgrade <version> --comms usb

For example, this command installs the latest stable release and sets the communication method to USB.

rrf_upgrade latest-stable --comms usb

Tip: Use latest-stable for the newest stable release, latest-unstable for the newest unstable release, or a specific version number, for example 3.5-rc.2.

Note: If RRF is already installed and you only want to change the communication method to USB, run rrf_upgrade set-comms usb instead. This does not reinstall the firmware.

Wait for the command to finish before you continue to the next step.

Flash the Firmware

Use an SD card to flash the firmware onto the SKR3EZ H723.

Rename the firmware file to firmware.bin.
Put firmware.bin in the root folder of a FAT32 formatted SD card.
Put the SD card into the SKR3EZ H723.
Power on the SKR3EZ H723 (using USB power or 12/24V power).
Leave the SKR3EZ H723 powered on for 1 to 2 minutes. This gives the board enough time to flash the firmware.
Power off the SKR3EZ H723.

Tip: You can check that the firmware has flashed correctly. Look at the SD card on a computer. If the file name has changed from firmware.bin to firmware.cur, the firmware has flashed correctly.

Connect the Board

Remove the SD card from the SKR3EZ H723.
Connect the SKR3EZ H723 to the SBC using a USB cable.

First Boot

Note: These steps assume the hostname of your SBC is duet3. If you changed the hostname in the ‘OS Customisation’ settings, use that hostname instead of duet3.

Turn on power to the SKR3EZ H723 and the SBC.
Wait for the SBC to boot. The first boot takes about 1 minute, and the SBC restarts two or three times during this time. Later boots take about 30 seconds.
If you did not set up your Raspberry Pi using the ‘OS Customisation’ settings in Raspberry Pi Imager, Raspberry Pi OS will ask you for this information now. Connect a screen and a keyboard to the SBC so that you can see these messages and respond to them.
1. Set the keyboard language.
2. Set a username and password.
Setup finishes and shows a command prompt. To set up WiFi and SSH, log in using the username and password you just created. Then type sudo raspi-config and press Enter.
To set up WiFi, select ‘System Options > Wireless LAN’. Select your country, then enter your WiFi network name (SSID) and password.
To set up SSH, select ‘Interface Options > SSH’ and enable it.
Select ‘Finish’ to close the configuration tool.

Tip: If you are using the ‘full’ version of DuetPi with a screen attached, the SBC boots and then the Chromium browser opens DuetWebControl in full screen automatically. Press F11 to exit full screen and see the Raspberry Pi desktop.

If you are connecting over the network, open a web browser and go to http://duet3.local/.

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