@jay_s_uk
Yes I did have it in that instance as I have been moving between the two trying to get something to work, after I removed it and rebooted with just the SBC microSD it remained in standalone according to the M122(as well as becoming completely unresponsive to the PanelDue, so I just reimaged the SBC microSD to have a "clean" DuetPi install. Then restarted the system with that reimaged SD in the SBC and nothing in the Duet 3, both HDMI output and the duet.local web interface just say failed to connect to duet3.local.
Doing the M122 readout again it does seem to be in SBC mode now, but obviously no functionality at all.
=== Diagnostics ===<LF>RepRapFirmware for Duet 3 MB6HC version 3.3 (2021-06-15 21:45:47) running on Duet 3 MB6HC v1.01 or later (SBC mode)<LF>Board ID: 08DJM-9P63L-DJ3T8-6JKD6-3SD6S-1U4M8<LF>Used output buffers: 1 of 40 (1 max)<LF>=== RTOS ===<LF>Static ram: 150904<LF>Dynamic ram: 59980 of which 0 recycled<LF>Never used RAM 143308, free system stack 200 words<LF>Tasks: SBC(ready,4.2%,606) HEAT(delaying,0.0%,405) Move(notifyWait,0.0%,352) CanReceiv(notifyWait,0.0%,944) CanSender(notifyWait,0.0%,374) CanClock(delaying,0.0%,339) TMC(notifyWait,7.0%,93) MAIN(running,88.8%,1272) IDLE(ready,0.0%,29), total 100.0%<LF>Owned mutexes: USB(MAIN)<LF>=== Platform ===<LF>Last reset 00:05:00 ago, cause: power up<LF>Last software reset time unknown, reason: User, GCodes spinning, available RAM 109240, slot 0<LF>Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0044a000 BFAR 0x00000000 SP 0x00000000 Task MAIN Freestk 0 n/a<LF>Error status: 0x00<LF>Step timer max interval 14997<LF>MCU temperature: min 14.4, current 23.3, max 23.5<LF>Supply voltage: min 23.8, current 23.9, max 23.9, under voltage events: 0, over voltage events: 0, power good: yes<LF>12V rail voltage: min 12.1, current 12.2, max 12.2, under voltage events: 0<LF>Heap OK, handles allocated/used 0/0, heap memory allocated/used/recyclable 0/0/0, gc cycles 0<LF>Driver 0: position 0, standstill, reads 45558, writes 11 timeouts 0, SG min/max 0/0<LF>Driver 1: position 0, standstill, reads 45558, writes 11 timeouts 0, SG min/max 0/0<LF>Driver 2: position 0, standstill, reads 45558, writes 11 timeouts 0, SG min/max 0/0<LF>Driver 3: position 0, standstill, reads 45558, writes 11 timeouts 0, SG min/max 0/0<LF>Driver 4: position 0, standstill, reads 45558, writes 11 timeouts 0, SG min/max 0/0<LF>Driver 5: position 0, standstill, reads 45559, writes 11 timeouts 0, SG min/max 0/0<LF>Date/time: 1970-01-01 00:00:00<LF>Slowest loop: 0.12ms; fastest: 0.00ms<LF>=== Storage ===<LF>Free file entries: 10<LF>SD card 0 not detected, interface speed: 37.5MBytes/sec<LF>SD card longest read time 0.0ms, write time 0.0ms, max retries 0<LF>=== Move ===<LF>DMs created 125, maxWait 0ms, bed compensation in use: none, comp offset 0.000<LF>=== MainDDARing ===<LF>Scheduled moves 0, completed moves 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1<LF>=== AuxDDARing ===<LF>Scheduled moves 0, completed moves 0, hiccups 0, stepErrors 0, LaErrors 0, Underruns [0, 0, 0], CDDA state -1<LF>=== Heat ===<LF>Bed heaters = -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamberHeaters = -1 -1 -1 -1<LF>=== GCodes ===<LF>Segments left: 0<LF>Movement lock held by null<LF>HTTP is idle in state(s) 0<LF>Telnet is idle in state(s) 0<LF>File is idle in state(s) 0<LF>USB is ready with "m122" in state(s) 0<LF>Aux is idle in state(s) 0<LF>Trigger is idle in state(s) 0<LF>Queue is idle in state(s) 0<LF>LCD is idle in state(s) 0<LF>SBC is idle in state(s) 0<LF>Daemon is idle in state(s) 0<LF>Aux2 is idle in state(s) 0<LF>Autopause is idle in state(s) 0<LF>Code queue is empty.<LF>=== CAN ===<LF>Messages queued 1502, received 0, lost 0, longest wait 0ms for reply type 0, peak Tx sync delay 0, free buffers 49 (min 49), ts 1502/0/0<LF>Tx timeouts 0,0,106,0,0,0 last cancelled message type 30 dest 127<LF><LF>=== SBC interface ===<LF>State: 0, failed transfers: 1, checksum errors: 0<LF>Last transfer: 271128ms ago<LF>RX/TX seq numbers: 0/1<LF>SPI underruns 0, overruns 0<LF>Disconnects: 0, timeouts: 0, IAP RAM available 0x2c83c<LF>Buffer RX/TX: 0/0-0<LF>ok<LF>
Something I have noticed is that when using BalenaEtcher it always seems to say imaging failed just before finishing the verification process, but when I use the Win32 Disk Imager there are no error notices etc. It is a 16GB SanDisk Class 10 microSD, but I have had it a while.