[][][Xperia 10II] losing cellular network after call

Glad you made this observation because it could help finding the true reason for the annoyingly long network pause after each call.

It is about the same time when I got my Xperia 10ii and t-mobile canceled 3G. Therefore I might have wrongly assigned the long network loss after every call to the switching-off of 3G - and not to SFOS/aarch64. I will check with my older back-up XA2 in order to confirm your observation

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This annoying bug still exists in SFOS EA. It is exasperating…


Yes, it is annoying. On my XA2 Plus I have also no Internet/Data Connection during the calls.

Five days ago I tried to fix this bug by flashing the phone with Android 11. I used it for a day, making and receiving calls. Both to different mobile providers and to landlines.
I sent and received text messages and surfed the internet.
Then I flashed SFOS Unfortunately without result, the bug is still present.

@flypig Why have you tagged this bug report as fixed?
Have you fixed this internally and will we get it with the next OS update?
The bug is still present in SFOS

Hi @silta, Thanks for pinging me about this: I’m glad you’re on the ball keeping track of things.

The community bug coordination team is cleaning up the bugs in the forum, and one of the steps has involved tagging all bugs that are noted in the release notes as having been fixed. There are over a hundred bugs like this, so there’s always a risk we make a mistake in the process.

In this case, this bug was reported as fixed in the release notes for Sailfish OS 4.2.0 Verla (it’s the very last bug in the list there).

Looking through our internal database, a number of changes were made to fix this issue, the decisive one being this change.

However, clearly you’re still experiencing problems.

It’d be really helpful to know whether the problems you’re experiencing now are identical to the ones you describe in your original bug report, or whether there have been any changes resulting from the fixes that have gone in?

Hi @flypig. The fixed bug in the relaese notes 4.2. does not refer to my bugreport. It refers to post #19 by @KuroNeko in my bugreport.
Unfortunately, he “hijacked” my thread.

Here again in brief:

german t-mobile simcard in X 10 II.
mobile data active.
After a phone call, the entire connection to the mobile network breaks down after the symbol for 2G appears very briefly in the upper right corner.

Even after deactivating flight mode or switching on the phone, it takes a very long time until a connection to the mobile network is established.

The loss of connection to the mobile network after call does not occur if there is a connection to a Wi-Fi network at the same time.

It should be noted that T-mobile Germany has already switched off 3G.

Interestingly, the exact same SIM card works in an Xperia X under the same conditions without any problems.

I recently tested all this with a Vodafone SIM card to rule out the possibility that it was due to the German t-mobile network.
Unfortunately, the result was the same.

That’s why I think it’s because of the 64bit version of SFOS.


I may add that I have exactly the same behavior @silta is experiencing with X10 and Vodafone Germany. With my XA2 and Vodafone the bug is not present. VF also shut down 3G a while ago.

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I also tested it several days ago with a Vodafone card. The same behaviour. I made an edit in my post before. Thanks for your confirmation.

Thanks for clarifying @silta, and for the confirmation @spark. That all makes sense now.

Concerning the original bug then, I can make a fresh internal bug report to cover it. However, one thing I want to be clear on is that this isn’t just the consequence of lack of VoLTE support on your phone.

I appreciate what you say about the fact your Xperia X doesn’t suffer from the same issue, but I just need to clarify.

Currently, without VoLTE support, and without a 3G network to fall back on, your phone will drop back to 2G during a call, meaning there’s no data connection. This is all correct behaviour. After the call it should then return to 4G with a data connection.

Is the Xperia X nevertheless dropping to 2G and then returning back to 4G quickly? In the case of your Xperia 10 II, if I understand correctly you see the same behaviour except that it takes considerably longer to return to 4G (could you clarify how long in both cases please?).

I’m sure I’m repeating things that you’re well aware of, or have already covered above, but it’s just helpful for me to be certain about these points.

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yes, understood and correct. The issue (for me) with the Xperia 10 lies in the long period to get back to 4G with no network at all meanwhile. As stated, after the call (which took place in 2G) the phone is without network, supposingly while trying to re-establish the 4G connection. This usually takes 20-30 seconds, even while being in a city center with perfect coverage.

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I’m aware of that.

Yes, the Xperia X turns back to 4G immediately.
The X 10 II needs mostly 20 - 60 seconds. During this time there is no cellular network available.

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On O2-Germany it also takes about 10-20 seconds (but not 60) to reestablish 4G connection after a cellular (2G) call (or call attempt). Don’t know if 3G is still in use at all.
I understand this behavior might be annoying for some users (while it doesn’t really bother me) and I expect this issue to be fixed (or vanish automatically) once VoLTE functionality is available eventually.

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As a someone working in telecom it sounds odd that the OS would be able to influence this, or especially be the prime suspect.
The only fair comparison would be Android vs Sailfish on the same hardware.
Xperia X vs Xperia 10 II can have a couple of dozen other differences in modem firmware and capabilities, e.g. band support.

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I am also experiencing this “bug” and believe it is due to too long a gap until the phone establishes a new 4G connection after finishing a call (which now is 2G). I hope VoLTE support will fix this. (Xperia 10 II, SFOS 4.4, Deutsche Telekom SIM)
So basically confirming the other reports

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Thank to everyone for all the helpful clarifications and confirmations.

I’ve created a fresh internal bug about this, and will removed the “fixed” tag while leaving it marked as “tracked”.

What would be really helpful would be to test it again after the VoLTE changes have rolled out (no date for this yet). As @Inte points out, it’s reasonable to suppose that this will address the issue, so if it doesn’t that’ll be particularly important to know about.

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Just one naive idea that might have been brought up earlier: Is it possible that the phone/sailfish simply checks for 3G networks first and due to the absence of this network it takes these 20+ seconds to an imaginary “3G search timeout” until the 4G search is performed?

How does this VoLTE-Theory match to my observation, that this only happens if WiFi is off? ([][][Xperia 10II] losing cellular network after call - #23 by fridlmue)

Jolla got ofono logs from me with WiFi on and off in zendesk issue #38217.

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It does not relate to that at all. Having VoLTE would remedy having to switch technologies in the first place - thus not have any issues switching back.

So from my observation:
4G network reconnects immediately if WiFi is on and in the very same spot it looses the network totally after a call for these 10-30 seconds if WiFi is off.

So if all of this issue is connected to the CSFB handling of the phone or the network and not the OS, how could it be that it is working in one of the cases. So I would still suspect that there should be a solution for this bug on the OS scale not requiring us waiting for a final VoLTE Implementation as workaround?! :wink:

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