S21 Ultra No Network Conection after the last Update

[Juan greenfield]

Hi, I have a S21 Ultra since late January, I had issues in the past but now since the last Update 3 days ago My Mobile Network stopped working, I have an (Ø) symbol not even empty bars, the SIM card works great on other devices, but non SIM card works on this device, I tried reseting the network settings, Wiped cache partition, factory reset, airplane mode on and Off, looks like the antenna stopped working completely, not a single SIM card works on this device.

I have Wifi connection but is not what I bought this phone for, I want network service, is there any other solution I can try?

 

[gpaolo79]

How can it be a mainboard issue if it was the update to Android 12 that triggered all this mess?

[tploumen]

Don't ask me why. You can try to revert back to Android 11 using Odin. You will find out that your problem still exist. 

[Members_7Q0Verw]

Hey, been having the same issue here. Here is the weird part. This started after I updated to Android 12. And the second weird part is that SOMETIMES when I restart the phone in safe mode, the signal comes back. I've tried clearing the mobile from 3rd party apps but nothing changed. Really weird issue that gets temporarily fixed with safe mode, but not always. I'm getting a replacement. Definitely expected more from a 1400 euro phone. Disappointed.

[GaborB]

Changed sim-card sill got the problems sometimes.
Looks like the only solution the mainbord replacement like the other said.

nice. clean my phone before service amazing. And then install all again is really what i hate.

[raddie]

I had the dreaded no signal problem randomly. Phone would cycle between no signal 5G, 4G, H ten no signal. Sometimes for 30 min. Almost never with WIFI, though. Tried factory reset, different SIMS, eSIM, cache partition clearing etc. Finaly I got fed up and broug it to Samsung service. Samsung replaced the motherboard and the phone it is fine now. The phone was repaired the same day. Save yourself the headache and take advantage of warranty cover. It will only cost you one factory reset when new motherboard is installed.

[gpaolo79]

I tried to ask for a motherboard replacement. They really pushed to avoid it, saying that it will come back because it's a software issue, not a hardware issue.

I had a thought... What is it's a problem of the image loaded on the phone? Obviously when they install a new motherboard they reload a brand new image. Has anyone tried to re-flash the phone? I'm going to ask next week to the support centre if they can do it.

[tploumen]

The only downside is: you now have a refurbished phone. You can check this yourself by installing https://play.google.com/store/apps/details?id=org.vndnguyen.phoneinfo

[raddie]

I forgot to mention I did the reflashing as well. Don't bother, push for motherboard replacement.

[raddie]

Maybe, but better than non working phone. Still covered by regular manufacturer warranty. 

[tploumen]

Can you check what it says in your case?