*** nasty bug in S21*** network search is buggy

[jk747]

Basically when roaming starts the S21 tends to lose it's data connection. After a lot of testing this bug is now reproducible when on a roaming network:

1. Turn select network operator automatically off , then select e.g. your home operator.

2. In my test this was Vodafone, guess what 5G connected; bandwith superb.

3. Activate airplane mode for e.g 20 seconds

4. Deavtivate airplane mode

5. After about 60 seconds connection re-established on the Voda GSM network; no more data! 

6. Ok no problem just do a manual scan networks operation, after about 90 seconds:" error searching for networks"

7. Game over no data ; internet access killed by a Samsung bug in the S21.

Hopefully the Samsung engineering team is allowed to look into this bug. I am sure there are still some S21 active S21 users around the globe.  Would be nice if this major bug gets resolved.!!!

[Pugs1957]

Have got the correct APN settings for Vodafone on your phone?

[jk747]

Hi Pugs, tx for your reply. If it only was so simple. ...When following the steps to reproduce the problem: there is no change in any APN or other operator network setting. Therefore there must be a bug in the cellular modem firmware and or a bug in Samsung Android interface to the cell modem....

[Pugs1957]

Hi, sorry, what I was trying to explain was you need both providers' APNs in the phone in the first place so the phone can select the appropriate one. Does that make sense?

[jk747]

Maybe I should explain the bug in a better way:

1. Roaming on Vodafone 5g   all ok

2. Activate air plane wait 20 sec deactivate ( stay in the exact same location)

3. BUG hits, reconnect to Vodafone ( same network ,still roaming). Now internet is dead,you only can do voice calls , no 5g , just old school GSM.

3.

[Pugs1957]

Got it, thank you. Hmm, not sure where the issue lies. Certainly sounds like a bug but it would be interesting to try this with another carrier but I'm leaning towards a bug as you say.

[jk747]

After even more testing I discovered a very weird BUG reproduction pattern:

1. All fine 5G roaming high speed

2. Reboot

3. Internet / data roaming dead; voice ok

4. Reboot again

5. 5G is back .....

One can repeat the above sequence endlessly the BUG remains on and off; this is really odd behaviour and must be an interesting issue for Samsung to resolve?

[jk747]

After thinking about this really weird BUG pattern,  I am suspecting the network search algorithm has bugs. The decision making between 5G and GSM 2G/edge, probably taking into account signal strengths is just no good. I noticed other posts in this forum describing similar issues.( Please note I have not ever experienced this bug on the home Vodafone network.)

[jk747]

This issue maybe related to Samsung(faulty) LTE commercial band blocking algorithms for each country?

[-Robot-]

Or as your roaming maybe the partner network is having issues