S21 ultra Signal loss problem after uploading to one ui 7

[Ahmadi]

After updating my S21 Ultra to one ui 7 android 15 , I have a problem with the network connection.

The network is completely disconnecting and goes into emergency mode, or it loses the antenna altogether, and I need to restart my phone every time to be able to connect to the network again. 

[Mujibar]

Reset mobile network settings under settings, general management, reset.

If you didn't clear your device cache after the update, make sure you do that also.

[comstock9c]

Tried resetting mobile networks, clearing cache, and factory reset. Nothing fixed the issue and Samsung tech support was useless. Basically feel stuck with a 1,200 dollar paperweight!

[comstock9c]

Also switched to an eSIM and that didn't help either.

[realaud]

Have you run a diagnostic on the phone?  Signal issues, absent a faulty antenna, are the domain of the carrier.  They get the updates and tweak them for their networks before pushing them out to users.  If you have not contacted your carrier, it is advisable to do so.  If you are the only customer having the issue, they should be able to help you with it (again, absent a faulty device), if you are one of  a multitude of customers with the issue, they need to know about it.  Make sure you ask for tech support and not customer service - and stay away from the carrier store, there are no techies there - their function  is to sell devices.

[SoloQuest74]

If all else fails, you may need to clear the partition on your device after a large software update. It was recommended to do so after the UI 7.0 update. Also backup your data and do a factory reset. Those things should help with your issues.

[Pianodude58]

@Mujibar had already posted that earlier.

[VoidedJaguar164]

I've had nothing but trouble since the last update. I have to be at home connected to Wifi to be able to do anything. If I'm away from home and not connected to Wifi, nothing works. It shows 5 bars of 5G one second, the next the no sign(🚫) pops up and it says "Searching for Network" or "Emergency Calls Only". I can't use any apps that require data. Sometimes I can't even send a text message. When it shows 5 bars of 5G I can go into my phone status and check my signal strength, and the signal is weak, although I've got 5 bars. I've never had any problems until the update. Now I'm getting a new phone because my current phone is pretty much unusable. 

[Mujibar]

That sounds like a carrier issue. Have you checked with your cell service provider?

[meself]

Refresh the network in connection also clear the phone cache

[ztzrico]

No, it is not a carrier issue. There are quite a lot of people experiencing the same issue. I

I had similar issue with my s23. Phone was bricked after one ui 7 update. I thought it was due to the one ui update, like a software issue. I flashed the firmware to the newest version. Didn't work. I even reverted it to older versions. Didn't work either... After some research, I found out that it's likely caused by faulty USB charging board. It turns out that this is a quite common issue with s21,22 and 23. Somehow the antenna is relying on the charging board.

I had the USB charging board replaced. And it worked! Repair kits are available for 15 bucks online. It took me 30 min to replace it. Or you can have someone do it for like $100.