topic Re: Boot reason: watchdog reset (cause: 0x3) in My Router

Boot reason: watchdog reset (cause: 0x3)

ParkInLondon — Mon, 24 Feb 2025 17:22:05 GMT

Hi,

My "Plusnet Hub One" is causing more and more issues. More than a year ago, the DHCP server function started acting up, which I worked around by running it from a Raspberry Pi, but now the hub is also additionally crashing/rebooting regularly:

When it happens, all devices disconnect from the network at first; the hub becomes completely unreachable for some time and then stays offline for some additional time before an internet connection is established.

The event log shows

>17:05:27, 24 Feb. ( 18.230000) Boot reason: watchdog reset (cause: 0x3)

This is really inconvenient, especially when someone is WFH...

What can I try to resolve this issue?

Re: Boot reason: watchdog reset (cause: 0x3)

jab1 — Mon, 24 Feb 2025 17:27:53 GMT

@ParkInLondon How old is the Hub? This sounds like failing hardware, and the only solution is a replacement.

Re: Boot reason: watchdog reset (cause: 0x3)

ParkInLondon — Mon, 24 Feb 2025 17:41:28 GMT

I think we switched to Plusnet around 2019/2020 and had it since then…

Re: Boot reason: watchdog reset (cause: 0x3)

jab1 — Mon, 24 Feb 2025 17:50:40 GMT

OK. My suggestion in that case is to call Customer Support (0330 123 9123) and tell them you have a failing router - they should offer to replace it for the £6.99 P&P charge.

Re: Boot reason: watchdog reset (cause: 0x3)

outcast — Mon, 24 Feb 2025 18:43:50 GMT

@ParkInLondon wrote:

What can I try to resolve this issue?

The most likely thing to cause these types of issues are failing capacitors in the mains power supply wall plug.

If you have a multimeter, you could check that the voltage at the DC connector is within 10% of the voltage stated on the plug.

Alternatively, if you have any spare power supply plugs from any old electronics that has the same voltage, similar wattage, and identical plug size, just substitute a different power supply to see whether the problems disappear.

Another cause could be that over time, the router's configuration might have become corrupted, perhaps due to mains outages, etc. You could try performing a FACTORY RESET to completely clear the settings, and hopefully start again from fresh.

According to the Plusnet help page for the Hub One - https://www.plus.net/help/broadband/router-user-guides/hub-one/

If you're having problems with setting your router up, it might be worth resetting it. Use a paper clip, pen, or something pointed to press in the reset pinhole button on the back of the router. Keep the button pressed for 20 seconds. When the light on the front of your Hub turns green, release the reset button. When the light on the front of the Hub turns blue, it's now restored to factory settings. Keep in mind that if you do this, it'll completely restore your router to the settings it had when it arrived. So if you've made specific changes to your settings, they'll need to be made again.

Re: Boot reason: watchdog reset (cause: 0x3)

jab1 — Mon, 24 Feb 2025 18:46:32 GMT

@outcast As this is an old Hub, and noting the error code and reason, I very strongly suspect it is the hardware itself at fault. PN should replace it without question.

Re: Boot reason: watchdog reset (cause: 0x3)

Dan_the_Van — Mon, 24 Feb 2025 19:08:10 GMT

@outcast

0x0: normal watchdog reset
0x1: watchdog reset caused by wireless PCI failure
0x2: watchdog reset caused by kernel not responding to interrupts
0x3: Returned if both bits 0x1 and 0x2 are set

Re: Boot reason: watchdog reset (cause: 0x3)

jab1 — Mon, 24 Feb 2025 19:12:53 GMT

So, as said by Bob Pullen in a couple of other topics on this subject - the router is failing, and needs replacement.

Re: Boot reason: watchdog reset (cause: 0x3)

ParkInLondon — Mon, 24 Feb 2025 20:51:32 GMT

I guess I will reach out to them tomorrow then. Thanks

Re: Boot reason: watchdog reset (cause: 0x3)

Anonymous — Mon, 24 Feb 2025 21:24:58 GMT

@outcast wrote:

"If you have a multimeter, you could check that the voltage at the DC connector is within 10% of the voltage stated on the plug."

In my experience, a failing switched mode power supply will often still indicate its rated voltage when measured "off-load" due to the tiny load that the test meter would put on it. It is often only when on-load that the output voltage drops.

I agree that testing "on load" will be difficult, but don't take a good reading off-load to mean that the PSU is definitely OK.

Re: Boot reason: watchdog reset (cause: 0x3)

jab1 — Mon, 24 Feb 2025 21:26:31 GMT

@Anonymous The suggestion you refer to above is pointless in this situation, although I appreciate you probably know this.

Re: Boot reason: watchdog reset (cause: 0x3)

Anonymous — Mon, 24 Feb 2025 21:31:40 GMT

@jab1

Oh yes, it was a general observation about testing switched mode power supplies without an effective load and assuming that a good result "proved" that the PSU was not faulty.

I got caught out myself like that when switched mode supplies were relatively new things - until I realised my mistake!

Re: Boot reason: watchdog reset (cause: 0x3)

ParkInLondon — Wed, 12 Mar 2025 15:44:12 GMT

Update for everyone:
I contacted customer support about replacing my 4+ year old hub, but the agent on the hotline refused. According to their line test, I had no downtime in the past seven days—despite experiencing eight reboots last month due to the 0x3 error. Apparently, they’ll only replace it if I agree to a contract renewal (which I won’t). Fantastic customer service, won't be a client for much longer.

Re: Boot reason: watchdog reset (cause: 0x3)

jab1 — Wed, 12 Mar 2025 16:26:00 GMT

@ParkInLondon To be honest, I'm not totally surprised about your experience - call centre staff these days work from crib-sheets, and have zero real knowledge.

That error code clearly indicates failing hardware, whether PN can 'see' the disconnections or not - and to be honest, if they looked in the correct place they would.

@MisterW Are you still around to comment on this, please?

Re: Boot reason: watchdog reset (cause: 0x3)

MisterW — Wed, 12 Mar 2025 16:47:52 GMT

It is failing hardware!. However the router is an 'old' router and therefore isnt 'on-loan' like recent ones. It is the property of the customer and is long since out of any warranty. I can see why, in this case, the agent was only able to supply a free replacement if the customer was willing to recontract.

Re: Boot reason: watchdog reset (cause: 0x3)

jab1 — Wed, 12 Mar 2025 16:52:08 GMT

Fair enough, @MisterW - I kind of get that, so the question then gets back to the customer - why don't they want to re-contract?

Re: Boot reason: watchdog reset (cause: 0x3)

outcast — Wed, 12 Mar 2025 17:31:35 GMT

@ParkInLondon wrote:

This is really inconvenient, especially when someone is WFH...

If it was me, and if "WFH", I wouldn't even bother trying to get any replacement basic ISP branded router.

It is easy to get really high spec routers, with "WFH" features including QoS and VPN end points, for cheap on eBay.

My most recent broadband router acquisition normally retails for £125, but won on eBay "as new, complete & boxed" for £16.08.