No Android 13 update

[martandbecs]

Hi all

I have a S21 ultra which is still running android 12, UI 4.1 and hasn't had a security update since September 2022. When I check for updates it says its upto date. I've tried through smart switch and that also says its upto date. 

Any ideas?

[Pugs1957]

Thanks. This is strange, I had expected a mismatch between the carrier and the firmware.
Please could you download the Root Checker app from Play Store, run it and let me know the result.

[martandbecs]

Is this what you mean?

[UNKNOWNUSERNAME]

can you not back it up?

[Pugs1957]

Yes, thanks. I remember reading about this see https://xdaforums.com/t/no-otas-if-you-change-csc-from-carrier-to-unbranded-eux-or-euy-s22-series.44...

It's a very long thread but I think the CSC was changed by an application which subsequently preventing updates and restoring the original CSC would restore updates.

The thread is more interesting towards the end.

[martandbecs]

Ok, so I'm going to probably sound thick now. How do I get around this and get it back to getting updates?

[Pugs1957]

No, you don't sound thick, it's pretty complicated how they arrived at the conclusion. The solution is to change the csc to O2U. There is a free tool to do this. Check out XDA Developers.