Xenon resets - 7 Red flashes after SOS

My Xenon resets after several minutes of running vanilla firmwares.
I’ve tested it with Tinker and the LED blink one.
While the firmware is running fine, after few minutes, I’m getting an SOS followed by 7 red blinks, the Xenon resets and resumes work.

My other Xenon acts as a gateway and is stacked on an Ethernet board. No such phenomenon is observed on the gateway unit. It is running both firmwares - with no issues at all.

Naturally I’ve flashed the OS using the particle CLI flash command. Flashing was successful but Xenon keeps crashing

Is there something wrong with Xenon acting as a client?

Any suggestions?


What is your modem’s model? Is it an Arris?

I don’t know what you mean by my modem’s model. If you are referring to the one given by the ISP, I don’t think it has anything to do with this issue, as I’m using a WiFi network based on Ubiquiti Access Points.
Anyway, I will take your advise to install a firmware with a serial logger to see if additional information is provided.


Hello Yoram,

Yes, I mean the model installed by your ISP.

The link I sent, my case, and another case are all using Arris modems and all experiencing the same issue …

The distinguishing point is not necessarily the actual WiFi AP but the device that controls the DHCP IP assignments - mere APs usually don’t deal with that but let the upstream router/modem take care of that and hence the brand and type of that device is of interest.

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My router is Edgerouter by ubiquiti. The ISP modem is set in bridge mode.
Will check the router for IPV6 stuff

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I am also using Ubiquiti for my Wi-Fi, but my AP gets its internet from my ISP modem which is an Arris model. Ultimately all of the traffic still gets routed through this.

I’ve activated the logging function.
Unfortunately, when the Xenon starts to send SOS - nothing is dumped to the console. The serial connection disconnects and resumes once the Xenon restarts

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I posted something about my issues with an Arris router a few days ago… My Xenons never flash SOS due to the modem; the endpoints/joiners just never connect (fast blinking green).

On the weekend I was able to configure a DD-WRT/Linksys router to act as a DNS server rather than it just passing DNS requests to the Arris box, and connected its WAN port to one of the LAN ports on the Arris, and then configured the Xenon gateway to use the DD-WRT box for its wlan. That allowed my joiners to connect.

In theory this will be fixed in 0.8.0-rc.26 – but I don’t think that’s what the OP is experiencing.

@yoramro – can you try swapping the two Xenons roles – i.e. put your endpoint Xenon on the etherwing and reconfigure it to be the gateway, and the other Xenon to be the endpoint?

I have a mesh set up using a Xenon/etherwing and Xenon endpoint, and it’s been running fine for the last couple days. Both are running Device OS 0.8.0-rc.25.

Hello folks,

Wanted to follow-up with this thread to let everyone know that a fix for the SOS-7 issue has been released with v0.8.0-rc.27. The issues was tracked to a problem with the Nordic 802.15.4 driver. Instructions for upgrading are available below. We’d love to know if applying the release fixes the issue SOS-7 issue that you’re experiencing.

Note that we have seen some reports of change in behavior for rc.27 when users call the Mesh.subscribe() function within the setup() loop that can result in a separate SOS-10 code which we’re currently investigating. If this issue affects you, please note the following workaround.