3.5.1: Duet2+SBC firmware crash-loops

[resam]

I am running an Duet2 Wifi with the SPI adapter to connect an SBC.

I tried upgrading from a working 3.4.6 setup to 3.5.1 using apt upgrade. DCS, DWC, etc. all upgraded nicely. The reprapfirmware package also updated and flashed the new firmware as expected, however, then the SPI connection to the Duet2 failed to re-establish.

After some troubleshooting, it turns out, that installing the Duet2Firmware_SBC.bin for 3.5.1 on my Duet board, it will simply crash loop the board.

DCS fails to connect with:

May 04 16:27:56 voron DuetControlServer[952]: Duet Control Server v3.5.1
May 04 16:27:56 voron DuetControlServer[952]: Written by Christian Hammacher for Duet3D
May 04 16:27:56 voron DuetControlServer[952]: Licensed under the terms of the GNU Public License Version 3
May 04 16:27:57 voron DuetControlServer[952]: [info] Settings loaded
May 04 16:27:58 voron DuetControlServer[952]: [info] Environment initialized
May 04 16:27:58 voron DuetControlServer[952]: [warn] Restarting full transfer because a bad header format code was received (0xff)
May 04 16:27:58 voron DuetControlServer[952]: [fatal] Could not connect to Duet: Timeout while waiting for transfer ready pin
May 04 16:27:58 voron systemd[1]: duetcontrolserver.service: Main process exited, code=exited, status=69/UNAVAILABLE
May 04 16:27:58 voron systemd[1]: duetcontrolserver.service: Failed with result 'exit-code'.
May 04 16:27:58 voron systemd[1]: Failed to start duetcontrolserver.service - Duet Control Server.
May 04 16:27:58 voron systemd[1]: duetcontrolserver.service: Consumed 2.409s CPU time.

Flashing back 3.4.6 via USB and bossac is recovering the device.
When working with 3.4.6 I can use USB-serial to connect to the Duet2 directly and get this output:

<CONNECTED>
RepRapFirmware for Duet 2 SBC version 3.4.6
<DISCONNECTED>

After bossac-flashing the 3.5.1 binary, the USB-serial port vanishes and re-appears about once per second. This matches the LED next to the USB port on the Duet2 briefly flashing red. I can't capture any debug output on this USB-serial console as it disappears before I can connect.

I noticed that the 3.5.1 binary is using 927 flash pages (474572 bytes), while the 3.4.6 uses only 877 pages (448900 bytes).

Is Duet2 + SBC over SPI still a supported setup?

[chrishamm]

@resam I can confirm this problem and we're working on a fix. For the moment, you can use the 3.5.0-rc.4 2SBC build which does not suffer from this problem.

[chrishamm]

@resam I've updated the reprapfirmware package again with a working 2SBC build of RRF 3.5.1. A regular system update should work correctly now.

[resam]

@chrishamm Thanks! I installed the new package, and it updated fine - seems to work now!