Spontaneous reboots - discssion on possible causes

[3zet 100]

2 hours ago, brunoais said:

Does it also reboot if only one SIM inserted?

I had one SIM card first 2 weeks of phone usage and no issues at all. 

[EskeRahn 5,399]

4 hours ago, 3zet said:

My Pro1 restarts itself when I put it into a metal locker. WiFi connected, both SIMs inserted. 

Interesting! Do you know what network bands are active?

As relatively few reports this, I have a suspicion that it (for whatever reason) is limited to some specific bands.

I just tried here, and it did NOT boot it goes down to 3G, and then zero bars.

[3zet 100]

2 minutes ago, EskeRahn said:

Interesting! Do you know what network bands are active?

Any tip how can I check it? Device have non-rooted stock firmware. 

[EskeRahn 5,399]

8 minutes ago, 3zet said:

Any tip how can I check it? Device have non-rooted stock firmware. 

Well you could check what bands your carrier supports. That would limit it. In the can it might try to change band from the one actually in use, searching for alternatives in the can.

[divstar 164]

I've been using *#*#4636#*#* to check some network settings.

[FlyingAntero 825]

1 hour ago, 3zet said:

Any tip how can I check it? Device have non-rooted stock firmware. 

You can check with CellMapper to which network you are currently connected. Also, I found little bit similar case from xda with Xperia M5 phone. In that case the root cause was probably a faulty battery. Perhaps some band causes peak to the power consumption when connection is weak or network changes which leads to a reboot?

- https://forum.xda-developers.com/xperia-m5/help/xperia-m5-auto-shutdown-fix-temporary-t3356247

I need to drive 70km away from my home tomorrow so I am planning to put phone to wcdma only and check what happens.

[VaZso 1,997]

53 minutes ago, EskeRahn said:

Well you could check what bands your carrier supports. That would limit it. In the can it might try to change band from the one actually in use, searching for alternatives in the can.

For me, I have tried to check what bands my carriers support but it does not seem to be an easy task.

It seems both of them currently support only B3, B7 and B20 for LTE.
The provider which I don't use for data has B1 and B8 bands for 3G.
The other service provider which I have 4G and mobile data, only supports B1 for 3G.
Both of them have 2G as fallback (at 900/1800 MHz).

Looking at coverage map, the carrier I use also for data has good coverage for 4G but fair coverage for 3G and practically full coverage at 2G.
The other carrier has fair coverage for 4G but good coverage for 3G and practically full coverage for 2G.
That is by looking at their respective maps.

Near the specific place where I had reboot, the carrier which I use for data has some gaps in coverage of 4G and 3G so it may need to fall back to 2G which seems to be available.
The other carrier also has some gaps in 3G near that place so it may also need to fall back to 2G.

At other places of that motorway, there isn't really gaps in coverage of both carriers in their respective 3G/4G bands (if I look at 4G for data and 3G for the other carrier).

So I have a feeling the reboot may be caused during switching from B1/B8 to 2G or B3/B7/B20 to 2G.
Also, there is a place where the motorway goes through a few tunnels so both carriers have much worse signals for a while - maybe reboots were near that place but I am unsure. However, that place is on the suspicious part of the road - "some time" after these tunnels, we usually stop at a fuel station and eat something and both times I have noticed reboots here. Last time it was about 44 minutes and I think that station is about 30-40 minutes after those tunnels - also there is no 4G coverage of my carrier what I use for data at that fuel station, it only has EDGE there.

Additional info - reboots were occurred somewhere in the morning (near 8-9am), so my battery should has been above 80-90% of charge, so I would not think of high voltage drop of battery as a cause of reboots.

[EskeRahn 5,399]

4 hours ago, VaZso said:

So I have a feeling the reboot may be caused during switching from B1/B8 to 2G or B3/B7/B20 to 2G.

Could well be. Interesting theory. I'm on a carrier not supporting 2G, so the phone won't try to go there (except emergency calls) So that could explain why I do not see the bug.

[wilhelmfitzpatrick 47]

So my spontaneous reboot adventure has taken an interesting turn. From the time I first got the phone, it was rebooting at least once, and sometimes several times a day. But starting about a week ago, with no software changes to speak of, this behavior has suddenly stopped, and I've not had a reboot since.

I can only assume that some dodgy trace on the motherboard "burned in" as a result of regular use.

Finger crossed that the reboots don't come back.

[EskeRahn 5,399]

2 minutes ago, wilhelmfitzpatrick said:

So my spontaneous reboot adventure has taken an interesting turn. From the time I first got the phone, it was rebooting at least once, and sometimes several times a day. But starting about a week ago, with no software changes to speak of, this behavior has suddenly stopped, and I've not had a reboot since.

I can only assume that some dodgy trace on the motherboard "burned in" as a result of regular use.

Finger crossed that the reboots don't come back.

My guess would be that after a period a lot of things are initialized and even cached, so your total system has less to do, and thus less 'stress' now than immediately after install.

Similar it is not unusual that the battery stamina on a charge is relatively poor just after an install. We usually don't register this, as the extra load is often drowned by the extra screen-on we usually have with a new phone.

[NiG 11]

16 hours ago, FlyingAntero said:

I had already forgot this message. I haven't changed any network settings so I believe that when I am using 3G either B1 (2100Mhz) or B8 (900Mhz) is selected. Those are bands that are used in Finland. B1 is usually used in cities and B8 outside cities. B8 might be the reason for reboots since I have faced reboots only when I travel between cities. There is a high change that B8 is used on those situations. If I am at home where 4G or 3G (possibly B1) is used I have no issues.

I also think that the reason for reboots in B8, because later I checked the phone with a SIM card of another carrier, that use 3G B1 (2100 MHz) only, and the phone did not reboot.

I gave this information to tech support.

[VaZso 1,997]

7 hours ago, EskeRahn said:

My guess would be that after a period a lot of things are initialized and even cached, so your total system has less to do, and thus less 'stress' now than immediately after install.

Similar it is not unusual that the battery stamina on a charge is relatively poor just after an install. We usually don't register this, as the extra load is often drowned by the extra screen-on we usually have with a new phone.

...or something has changed on carrier side - like a new transponder installed or something which was broken has been repaired or changed transceiver hardware (manufacturer / model) nearby.

As of battery, it should have a battery "fuel gauge" IC on the mainboard which monitors "incoming" and "outgoing" charge and has an accurate output which the system can use to show accurate percentages... but this IC has a learning curve so it needs some time to accommodate to the specific battery installed.
Without this IC, battery percentage can not be predicted easily or accurately.
Monitoring the voltage is not enough (but may be used to determine some not really accurate states) and monitoring actual voltages/currents by an own solution is maintainable but a bit harder than doing it by an IC designed specifically for this purpose.

[EskeRahn 5,399]

13 minutes ago, VaZso said:

As of battery, it should have a battery "fuel gauge" IC on the mainboard which monitors "incoming" and "outgoing" charge and has an accurate output which the system can use to show accurate percentages... but this IC has a learning curve so it needs some time to accommodate to the specific battery installed.
Without this IC, battery percentage can not be predicted easily or accurately.
Monitoring the voltage is not enough (but may be used to determine some not really accurate states) and monitoring actual voltages/currents by an own solution is maintainable but a bit harder than doing it by an IC designed specifically for this purpose.

People very often confuses the percentages shown with something meassured. In reality it is estimates - or less kind "guesses". A bit like the ETA of a train or plane.

A LOT of factors come in. The workload, the temperature, the age of the battery... See this ancient post.

[VaZso 1,997]

21 minutes ago, EskeRahn said:

People very often confuses the percentages shown with something meassured. In reality it is estimates - or less kind "guesses". A bit like the ETA of a train or plane.

A LOT of factors come in. The workload, the temperature, the age of the battery... See this ancient post.

That is why fuel gauge ICs came in view. Li-Ion kind of batteries can not be measured easily - near full charge, near medium charge and near low charge may have been predicted otherwise, but accurate percentage is not.

...but these ICs can do complicated calculations and predictions which may result in a really accurate percentage feedback.
However, if battery worn, this can also result in a turn off at relatively large charge amounts but in normal circumstances, they work well.

I think current mobile phones include this kind of circuit and I don't think that F(x)tec left it out.

I know my old Nokia feature phone did not have this kind of circuit, but it only had maybe about four bars and it remained near full charge for a long time, then dropped a bit and soon it was discharged. Today phones are much better this way.

Search for "Fuel gauge IC".

[MickH 211]

I'm pretty certain it's a network issue, as I've had the same issue with other phones and providers in the past.

This could be useful for diagnosing and locating which tower could be the culprit there's a wealth of info that may be useful.

https://play.google.com/store/apps/details?id=com.staircase3.opensignal&hl=en_GB

[sdx 45]

On 2/25/2020 at 10:06 AM, EskeRahn said:

Thanks, this strengthen the suspicion that it is related to when the carrier wants it to move from one cell tower to another. And as not happening more often, it could be specific band changes that the Pro1 fails at.

My device was crashing all the time, even with no SIM card inserted. Perhaps it was connected anyway, but it seems a bit far-fetched in this scenario. Anyway, I was just notified that a replacement device is on my way to me, after sending it in for repair. Let's see if it makes any difference!

[brunoais 317]

Different bug, I suppose

[FlyingAntero 825]

On 2/27/2020 at 7:38 PM, FlyingAntero said:

I need to drive 70km away from my home tomorrow so I am planning to put phone to wcdma only and check what happens.

I forced my phone to use only WCDMA and traveled that 70km but I was not able to produce random reboot. When I was driving back I selected GSM/WCDMA preferred but no reboot. I checked that my phone was connected to both B1 and B8 bands during the trip. This was a trip that I had not drove before so I don't know if there would be reboot with stock settings anyway.

22 hours ago, Toby Lerone said:

Sorry to hark back so far, but I had this last night.

My pro1 always crashes when I go home. I had both the 2.4G andf 5G wifi hotspots saved, and I guess it saw the 2.4 one first. I removed the 5G one from my saved networks, the phone crashed and then was stuck in an infinate reboot loop until I managed to turn off wifi just after it booted.

Removing the 2.4G one and re-adding the 5G one - it hasn't crashed since I've done that.

I started to think about a new scenario that maybe WiFi 2.4G issue is related to assumed network issue. I have 2.4G WiFi at home but I haven't faced reboots at home. Maybe there is a really specific usage scenario where both WiFi 2.4G and some network band are related?

[ddark-il 100]

11 minutes ago, FlyingAntero said:

I started to think about a new scenario that maybe WiFi 2.4G issue is related to assumed network issue.

Don't think so. In my case I was never connected to WiFi, during the reboot.

The theory with energy spike causing reboot seems more plausible, I have dual-sim with multiple mail and messenger accounts always syncing.

[Toby Lerone 17]

1 hour ago, ddark-il said:

Don't think so. In my case I was never connected to WiFi, during the reboot.

The theory with energy spike causing reboot seems more plausible, I have dual-sim with multiple mail and messenger accounts always syncing.

This energy spike thing could seem plausible. I also live in a large town in the UK which has good signal coverage, but my specific house has none. It could be the increase of transmit power to compensate for the loss of cellular signal combined with the reconnection of the device to my home wifi at the same time that causes this - maybe due to mail syncing at the same time, but I can't explain why 5Ghz doesn't seem to do the same.

It used to be even when I popped outside and the phone got a sniff of a cellular signal it would reboot too - didn't even have to arrive home just walk out onto the drive which suggests it might be increasing power to transmit. We have delivery robots - and whenever I get something from them just as I need my phone to unlock them it reboots!

[FlyingAntero 825]

I googled a bit and I think that I might have found something to resolve this issue. Some Sony Xperia devices (XZ1 Compact and XZ Premium) with same chipset (SD835, MSM8998) have also suffered from random reboots. There were very similar symptoms.

• "I'll add that it's still ongoing and I've noticed it happens in the same physical place with some consistency. I take a train for my daily commute and it usually happens in the area between two particular stations. Perhaps relevant is that this area has always had a bad radio signal."

 

• "I was able to reproduce it consistently during my commute home. For testing, I set up three XZ Premium devices to stream music over mobile-data using the YouTube Music app (this matches the log posted by bobobo1618). The mobile carrier was one of the top three largest carriers in Canada.

  All three devices would crash and reboot during my commute. pstore logs always showed the same error: "Fatal error on the modem"

  I also saw the same crash with a different top-three mobile carrier.

  The good news is that flashing the 47.2.A.2.33 firmware using Emma seems to resolve the defect.

  I did this to one of the three test devices and repeated my tests. The two non-upgraded devices continued to crash, but the third did not."

 

The issue was that modem crash caused system reset. See more information from below:

• https://github.com/sonyxperiadev/bug_tracker/issues/9

The issue was fixed with firmware update (47.2.A.2.33, December 2018). Interesting thing is that I have also XZ1 Compact but I don't remember that I faced random reboots with it before I changed to Pro1. The reason might be that I moved to another city in the beginning of 2019 when XZ1 Compact was already fixed. It is possible that the bug was not obtainable where I lived before.

@tdm Maybe you could comment this? Do you think that it is the same bug? There was also a work around presented.

• https://github.com/sonyxperiadev/bug_tracker/issues/9#issuecomment-451813295

[EskeRahn 5,399]

1 hour ago, FlyingAntero said:

I googled a bit and I think that I might have found something to resolve this issue. Some Sony Xperia devices (XZ1 Compact and XZ Premium) with same chipset (SD835, MSM8998) have also suffered from random reboots. There were very similar symptoms.

Very interesting, thanks! I tag @Waxberry to make sure he sees this, so It can be forwarded to the right people. 🙂 Especially interesting that they even got a workaround..

[Jordi 72]

3 hours ago, FlyingAntero said:

I started to think about a new scenario that maybe WiFi 2.4G issue is related to assumed network issue. I have 2.4G WiFi at home but I haven't faced reboots at home. Maybe there is a really specific usage scenario where both WiFi 2.4G and some network band are related?

With the first device I get, I had quite a few reboots at home when playing youtube videos through wifi. The reboots appeared when doing additional things like pressing volume up or down, etc. They sent me a second device which is far better in this regard but some reboots still appear from time to time, at home (during the night, phone idle).

[tdm 2,322]

Modem crashes are always fatal, eg. reboot AFAIK. And the modem software is completely closed source. The OEM may have the source, I don't know. If they do, I might be able to build a kernel that crashes to ramdump mode. This would allow you to pull a copy of the device state at the time of the crash and send it to the OEM for analysis.

[VaZso 1,997]

8 hours ago, FlyingAntero said:

The issue was that modem crash caused system reset. See more information from below:

• https://github.com/sonyxperiadev/bug_tracker/issues/9

The issue was fixed with firmware update (47.2.A.2.33, December 2018). Interesting thing is that I have also XZ1 Compact but I don't remember that I faced random reboots with it before I changed to Pro1. The reason might be that I moved to another city in the beginning of 2019 when XZ1 Compact was already fixed. It is possible that the bug was not obtainable where I lived before.

It may happen. I had only two reboots on the same road (Motorway) on the same direction of the road.

I have IMAP idle enabled and it reconnects in 15 minutes to IMAP server on connection lost. So it may happen it wanted to communicate on mobile data when I have reached a low signal place and modem crash occurred...