Poor connectivity after One UI 6.0 update

[Rayy973]

Hi guys. I own a Galaxy S21 ultra and it worked really well until I updated One UI. Now I'm having huge issues connecting to carrier's mobile data network (even if it shows the 4G/5G icon and that I have many connectivity bars). Most of the time apps indicate me that I'm not connected to the internet. But it also impacts phone calls and text messages. It's more than annoying. I tried factory reset. No success. I used my sim cards on another phone. It worked. The update messed with the connectivity of the phone and it seems many others reported the same behavior following that update. I can't find a word from Samsung about it. Did I miss it ? What do they need to fix this ? Class actions or something? It seems that downgrading to One UI 5.1 solved the issue for some people. How can i do that ?

[PghLei]

Mine been messing up since upgrading from the s10. T-Mobile told me to go to the store and get a new sim card. Hopefully that'll work

[Rayy973]

Did it work ? No luck for me.

[Popsicle20]

I've seen posts from several people who said they were able to fix issues like this by getting an updated sim card. I hope it works for you.

[Rayy973]

An updated sim card ? I asked for a new one and paid for it but no success.

[Surrahnicole]

At&t escalated my issue and had me go in an switch to a new esim and it did absolutely nothing. The only difference is that when I dial the *#*#4636#*#* code to check phone info/diagnostics, my data connection always shows connected now. Which just makes it harder to diagnose because now it SAYS it's working when it's not. Before it would switch to disconnected and suspended constantly. It's definitely a hardware or software issue on Samsungs end. All of the other phones on our plan are working perfectly. I can't make calls or send/receive texts until I get back home on wifi. Which makes my phone useless and my unlimited bill ridiculously high.

[Mannyj23]

Same thing happened to my samsung galaxy s21 ultra exynos. After updating to one ui 6.0 no mobile coverage. Have added apn for my carrier which didn't help. Reset mobile connection and cleared partition cache, tried it without a cover. Same issue. Tried on a new sim as well as other carrier sims (im a IT/mobile tech). Issue still remains, I dont want to wipe and roll back to 5.0 using odin as I have taken alot of time customising the phone and can't be bothered restoring it. Waiting for one ui 6.1 to hopefully fix the issue. In the meantime I am using my older phone where the sim card works with no issues. 

[novitaforlife]

Check if your phone info settings are set to NR/LTE/UMTS/EDGE.

[Roserosenrosen]

I've wasted hours and hours of frustration switching from T-Mobile to Verizon after updating to one UI 6. The problem is that many of the LTE bands are not properly recognized. I have a terrible signal but it should be much much better with this phone. Tragically Verizon keeps pointing fingers to Samsung and vice versa. I'm hoping that a 6.1 update fixes it or I'm switching to Apple. I thought buying a carrier unlocked phone would be an advantage but it looks like it's a nightmare.

[userblRUKdmh4F]

It's gotta be a Samsung issue. I have Tmobile and doing a sim switch and reset did nothing. I definitely noticed the problem after my UI 6.0 update and I have an S22 Ultra. Tmobile told me it's not them. I have to say if this doesn't get fixed soon, I'm out, Samsung. It's been fun, but you have too many problems anymore for it to be worth it. I use my phone for work and I've essentially been dead for 3 weeks now because of this. Time to brick and go back to a Google phone...