S21 update to Android 12 - SIM continuously resetting

[gpaolo79]

Hello,

three days ago I have received the update to Android 12 on my Galaxy S21 5G  and, since then, the phone is almost unusable to make phone calls

Both sims reset themselves periodically, within minutes, dropping the network and any phone call in progress. 

After trying to reset the network settings, the phone has started to request the pin for the sims at each reset, so I had to disable it. Keeping one or the other sim active only isn't changing the behaviour. 

The diagnostic on the phone doesn't detect any issue even if run while the network is down. 

Does anyone incurred in the same issue or found any solution? The phone is 3 months old...

[JLerrdh]

I'm not holding out any hope on a software fix for this. The phone is totally unusable for business purposes outside of WiFi, at present. Travelling to work I lose signal multiple times.

[gpaolo79]

I know. I'm waiting for 4.1 update and see if that works, otherwise I'll contact again Samsung for a repair.
The fact that on android 11 it works fine still makes me hope that they can fix it in software...

[JLerrdh]

Still sim cycling today. I've caught it on screen recorder and sent it to Samsung via the Members app in the hope they can resolve this quickly. I dont want a non working phone in mobile data areas for 2 months because of a botched update

[gpaolo79]

That's good, thanks for updating us. Let us know what Samsung says... If the say anything... 

[JLerrdh]

No update from Samsung support. Can I manually downgrade to android 11 at BULF if I use odin? Finding this lack of signal extremely annoying, worse than the S4 crashing issues years back. I couldn't recommend this phone to anyone based on these basic issues

[garethcia]

Just to update everyone. Since I had my motherboard, screen and battery replaced the bug has gone away so 110% hardware related 

[Erik Friis-Dahl]

An update from me.  I sent in the phone to my service provider a month ago.  They tried to fix it but were unable to do so.  The solution was to send me a new phone, so today I received a new phone and now everything works as it should.

[gpaolo79]

I still have hope for a software fix.
I'm still on A11, a few days ago I have added an esim. Real Sim + esim worked fine.
Before esim, two real Sim were working fine.
After esim, I went reactivated the second real sim, and they were resetting every five minutes like on A12.
I have forced the second Sim on 3G and I didn't have a single reset in the past five days.
Once UI4.1 comes out I'll give it a try. If it still doesn't work, then I'll ask for the repair.

[JLerrdh]

After months of asking I've finally got an engineer booked for a week and a halfs time. I'll update you with the result. 

[hasham11]

I ended up buying the S22 Ultra, got £580 for my S21 Ultra for trading it in whilst buying the new phone.