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?

 

[tploumen]

Yes, I have. But my problem was already solved because my mainboard was swapped at a Samsung Service Centre. But I'm 100% sure that I've read somewhere that the upgrade to android 12 fixed the problem. So I'm curious if it fixes yours too. Please keep us informed when your update arrives!

[Rūmøur]

That's great!! Really wish you could the link to where you read that the update solved the problem. It would be such a relief. Mine is the Hong-Kong version so sending it to samsung would mean I'd have to ship it all the way back to China which will be very time consuming.

[tploumen]

I understand. I thought I saved the link in my bookmarks, which is not the case. Now I can't find the post anymore. I'm almost certain it was on Reddit / XDA.

At the Service Centre, they didn't know what the problem was so they switched the mainboard. I'm almost certain the problem must be software related, since my problem happened right after the July security update. Software updates can't break hardware.

By the way since yesterday you can download the official Alpha version of Android 12 on https://www.sammobile.com/news/galaxy-s21-android-12-firmware-available-download/ and flash it with Odin. That's really easy to do.

Please report if Android 12 fixes your problem.

[Rūmøur]

Thanks!!! Should you come across the link again, I'd appreciate it if you leave it here. Will take a look at the alpha version and see if i can do the update. Will see how that goes!! Thanks again!!

[tploumen]

No problem. The Hong Kong firmware is available: https://www.sammobile.com/firmwares/

[Scooter80]

Hi. I have the same problem. Upgrading to 12 did nothing. I sent a screen recording to Samsung what happens after turning on LTE. Network disconnection and no internet. 

[tploumen]

Can you upload the screenrecording here...?

[Scooter80]

This happens non-stop as soon as I turn on LTE.

[tploumen]

I can't play the video, it says that its still processing.

Your LTE problem, is it random disconnects to circle symbol...? Or do you have no LTE at all...?

[Juan greenfield]

Hey guys update from my side, I used to have to reset network conectivity and the phone and then take off the sim and put it back on to have network conection about 5 to 6 times a day. Was about to send the device for another replacement (yes, second device with this problem) and today morning i recieved the One Ui 4 updated and since then the problem disappeared, don't know if that solved the issue, but so far so good, but definitely I need to wait at least a few days to confirm that this was the update or just luck for the day.