For anyone having similar issues: I solved it with with a custom bash script and systemd service for now.

It checks for an existing connection on eth0 and if it cannot detect one a hotspot on wlan0 is created.

#!/bin/bash

# ethernet_check.sh
# This script checks if the Ethernet cable is plugged into eth0 and manages the WiFi hotspot accordingly.

while true; do
    # Check if the Ethernet cable is connected to eth0
    if ethtool eth0 | grep "Link detected: yes" > /dev/null; then
        echo "Ethernet cable is plugged in. Disconnecting WiFi hotspot..."
        nmcli device disconnect wlan0
    else
        # Check if the hotspot is already running to avoid trying to start it again
        hotspot_status=$(nmcli con show --active | grep Hotspot)
        if [ -z "$hotspot_status" ]; then
            echo "No Ethernet cable detected and no active hotspot. Starting WiFi hotspot..."
            nmcli device wifi hotspot ifname wlan0 ssid YourSSID password YourPassword
        else
            echo "Hotspot is already active."
        fi
    fi
    
    # Wait for 10 seconds before checking again
    sleep 10
done

Make it executable with

chmod +x /usr/local/bin/ethernet_check.sh

Create a service to start it with the Raspberry Pi.

[Unit]
Description=Ethernet Hotspot Check Service
After=multi-user.target

[Service]
Type=simple
ExecStart=/usr/local/bin/ethernet_check.sh
Restart=on-abort

[Install]
WantedBy=multi-user.target

Reload systemd:

sudo systemctl daemon-reload

and enable the service to start on boot:

sudo systemctl enable ethernet_check.service

Then start the service or reboot.

For anyone having similar issues: I solved it with with a custom bash script and systemd service for now.

It checks for an existing connection on eth0 and if it cannot detect one a hotspot on wlan0 is created.

#!/bin/bash

# ethernet_check.sh
# This script checks if the Ethernet cable is plugged into eth0 and manages the WiFi hotspot accordingly.

while true; do
    # Check if the Ethernet cable is connected to eth0
    if ethtool eth0 | grep "Link detected: yes" > /dev/null; then
        echo "Ethernet cable is plugged in. Disconnecting WiFi hotspot..."
        nmcli device disconnect wlan0
    else
        # Check if the hotspot is already running to avoid trying to start it again
        hotspot_status=$(nmcli con show --active | grep Hotspot)
        if [ -z "$hotspot_status" ]; then
            echo "No Ethernet cable detected and no active hotspot. Starting WiFi hotspot..."
            nmcli device wifi hotspot ifname wlan0 ssid YourSSID password YourPassword
        else
            echo "Hotspot is already active."
        fi
    fi
    
    # Wait for 10 seconds before checking again
    sleep 10
done

Make it executable with

chmod +x /usr/local/bin/ethernet_check.sh

Create a service to start it with the Raspberry Pi.

[Unit]
Description=Ethernet Hotspot Check Service
After=multi-user.target

[Service]
Type=simple
ExecStart=/usr/local/bin/ethernet_check.sh
Restart=on-abort

[Install]
WantedBy=multi-user.target

Reload systemd:

sudo systemctl daemon-reload

and enable the service to start on boot:

sudo systemctl enable ethernet_check.service

Then start the service or reboot.

@chrishamm The services duetpluginservice as well as duetpluginservice-root are running and I can (de-)activate Plugins under Settings -> Plugins (e.g. the G-Code Viewer):

$ sudo systemctl status duetpluginservice.service
● duetpluginservice.service - Duet Plugin Service
     Loaded: loaded (/lib/systemd/system/duetpluginservice.service; enabled; preset: enabled)
     Active: active (running) since Mon 2024-03-11 15:12:35 CET; 7min ago
   Main PID: 848 (DuetPluginServi)
      Tasks: 9 (limit: 1585)
        CPU: 1.312s
     CGroup: /system.slice/duetpluginservice.service
             └─848 /opt/dsf/bin/DuetPluginService

Mar 11 15:12:34 revopitest systemd[1]: Starting duetpluginservice.service - Duet Plugin Service...
Mar 11 15:12:34 revopitest DuetPluginService[848]: Duet Plugin Service v3.5.0-rc.3
Mar 11 15:12:34 revopitest DuetPluginService[848]: Written by Christian Hammacher for Duet3D
Mar 11 15:12:34 revopitest DuetPluginService[848]: Licensed under the terms of the GNU Public License Version 3
Mar 11 15:12:35 revopitest DuetPluginService[848]: [info] DuetPluginService.Program: Settings loaded
Mar 11 15:12:35 revopitest DuetPluginService[848]: [info] DuetPluginService.Program: Connection established
Mar 11 15:12:35 revopitest systemd[1]: Started duetpluginservice.service - Duet Plugin Service.

$ sudo systemctl status duetpluginservice-root.service 
● duetpluginservice-root.service - Duet Plugin Service (root)
     Loaded: loaded (/lib/systemd/system/duetpluginservice-root.service; enabled; preset: enabled)
     Active: active (running) since Mon 2024-03-11 15:12:35 CET; 9min ago
   Main PID: 847 (DuetPluginServi)
      Tasks: 9 (limit: 1585)
        CPU: 1.297s
     CGroup: /system.slice/duetpluginservice-root.service
             └─847 /opt/dsf/bin/DuetPluginService

Mar 11 15:12:34 revopitest systemd[1]: Starting duetpluginservice-root.service - Duet Plugin Service (root)...
Mar 11 15:12:34 revopitest DuetPluginService[847]: Duet Plugin Service v3.5.0-rc.3
Mar 11 15:12:34 revopitest DuetPluginService[847]: Written by Christian Hammacher for Duet3D
Mar 11 15:12:34 revopitest DuetPluginService[847]: Licensed under the terms of the GNU Public License Version 3
Mar 11 15:12:35 revopitest DuetPluginService[847]: [info] DuetPluginService.Program: Settings loaded
Mar 11 15:12:35 revopitest DuetPluginService[847]: [info] DuetPluginService.Program: Connection established
Mar 11 15:12:35 revopitest systemd[1]: Started duetpluginservice-root.service - Duet Plugin Service (root).

Some codes mentioned here DuetPiManagementPlugin are working: M21, M22, M550, M586, M999

The other are not and are all throwing the same error message "On-board firmware cannot process network-related commands when using an attached Single Board Computer".

Yeah for sure! Here is the output:

M122
=== Diagnostics ===
RepRapFirmware for Duet 3 MB6HC version 3.5.0-rc.3 (2024-01-24 17:58:49) running on Duet 3 MB6HC v1.01 (SBC mode)
Board ID: 0JD2M-999AL-D2PS0-6J9F8-3S46N-9NKB1
Used output buffers: 1 of 40 (17 max)
=== RTOS ===
Static ram: 155184
Dynamic ram: 85188 of which 0 recycled
Never used RAM 105620, free system stack 214 words
Tasks: SBC(2,ready,0.7%,440) HEAT(3,nWait 6,0.0%,353) Move(4,nWait 6,0.0%,336) CanReceiv(6,nWait 1,0.0%,940) CanSender(5,nWait 7,0.0%,334) CanClock(7,delaying,0.0%,336) TMC(4,nWait 6,8.3%,56) MAIN(2,running,91.0%,444) IDLE(0,ready,0.0%,30), total 100.0%
Owned mutexes: HTTP(MAIN)
=== Platform ===
Last reset 00:03:54 ago, cause: software
Last software reset at 2024-03-11 08:55, reason: StuckInSpinLoop, Gcodes spinning, available RAM 105620, slot 0
Software reset code 0x4083 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0040080f BFAR 0x00000000 SP 0x2041b8b4 Task MAIN Freestk 1983 ok
Stack: 0041a123 0041a13a 210f0000 00000000 00000000 00000000 00000000 00000000 20439a4c 00000003 00000002 00000002 0004dfe0 20439a94 000001c2 2042fdd0 00000000 43425320 722c3228 74696157 0000003a 00000000 00000000 00000000 00014cc4 00000000 00000000
Error status: 0x00
MCU temperature: min 29.5, current 30.7, max 30.8
Supply voltage: min 23.3, current 23.4, max 23.4, under voltage events: 0, over voltage events: 0, power good: yes
12V rail voltage: min 12.0, current 12.0, max 12.1, under voltage events: 0
Heap OK, handles allocated/used 0/0, heap memory allocated/used/recyclable 0/0/0, gc cycles 0
Events: 0 queued, 0 completed
Driver 0: standstill, SG min n/a, mspos 8, reads 31176, writes 0 timeouts 0
Driver 1: standstill, SG min n/a, mspos 8, reads 31176, writes 0 timeouts 0
Driver 2: standstill, SG min n/a, mspos 8, reads 31176, writes 0 timeouts 0
Driver 3: standstill, SG min n/a, mspos 8, reads 31176, writes 0 timeouts 0
Driver 4: standstill, SG min n/a, mspos 8, reads 31176, writes 0 timeouts 0
Driver 5: standstill, SG min n/a, mspos 8, reads 31175, writes 0 timeouts 0
Date/time: 2024-03-11 09:00:12
Slowest loop: 1.45ms; fastest: 0.08ms
=== Storage ===
Free file entries: 20
SD card 0 not detected, interface speed: 37.5MBytes/sec
SD card longest read time 0.0ms, write time 0.0ms, max retries 0
=== Move ===
DMs created 125, segments created 0, maxWait 0ms, bed compensation in use: none, height map offset 0.000, max steps late 0, ebfmin 0.00, ebfmax 0.00
no step interrupt scheduled
Moves shaped first try 0, on retry 0, too short 0, wrong shape 0, maybepossible 0
=== DDARing 0 ===
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== DDARing 1 ===
Scheduled moves 0, completed 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1
=== Heat ===
Bed heaters -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamber heaters -1 -1 -1 -1, ordering errs 0
=== GCodes ===
Movement locks held by null, null
HTTP* is doing "M122" in state(s) 0
Telnet is idle in state(s) 0
File is idle in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger* is idle in state(s) 0
Queue is idle in state(s) 0
LCD is idle in state(s) 0
SBC* is idle in state(s) 0
Daemon is idle in state(s) 0
Aux2 is idle in state(s) 0
Autopause is idle in state(s) 0
File2 is idle in state(s) 0
Queue2 is idle in state(s) 0
Q0 segments left 0, axes/extruders owned 0x0000000
Code queue 0 is empty
Q1 segments left 0, axes/extruders owned 0x0000000
Code queue 1 is empty
=== CAN ===
Messages queued 614, received 0, lost 0, errs 576440, boc 0
Longest wait 0ms for reply type 0, peak Tx sync delay 0, free buffers 50 (min 50), ts 614/0/0
Tx timeouts 0,0,614,0,0,0 last cancelled message type 30 dest 127
=== SBC interface ===
Transfer state: 5, failed transfers: 0, checksum errors: 0
RX/TX seq numbers: 6092/6092
SPI underruns 0, overruns 0
State: 5, disconnects: 1, timeouts: 1 total, 1 by SBC, IAP RAM available 0x255cc
Buffer RX/TX: 0/0-0, open files: 0
=== Duet Control Server ===
Duet Control Server version 3.5.0-rc.3 (2024-01-26 12:37:35)
Code buffer space: 4096
Configured SPI speed: 8000000Hz, TfrRdy pin glitches: 0
Full transfers per second: 39.10, max time between full transfers: 40.7ms, max pin wait times: 28.3ms/0.9ms
Codes per second: 0.01
Maximum length of RX/TX data transfers: 4360/48

Hi everyone,

First of all, I apologize if I am in the wrong category - I am pretty new to this forum.

I was wondering if I am just misunderstanding the M589 Code or doing something wrong.

My setup consists of one MB6HCv1.01A Board with a Raspberry Pi 4 Model B. It's a fresh and minimal installation (v3.5.0-rc.3).

Now I am trying to setup the Duet in AP-mode (and optionally wired via Ethernet) with the M589 command, as the documentation https://docs.duet3d.com/User_manual/Reference/Gcodes#m589-configure-access-point-parameters says it is possible - even with a SBC setup, right?

I can connect via direct Ethernet connection and everything is working but as soon as I send the M589 or M552 or any other network related command the DWC always says:

Error: M589: On-board firmware cannot process network-related commands when using an attached Single Board Computer

allthough the documentation says "In SBC mode, sending this command makes a persistent change. It does not need to be added to dsf-config.g. It should NOT be included in config.g.".

So... what am I doing wrong?

Any help would be very much appreciated. Thanks a lot!