[Nokia 8.3 5G (8V 5G UW) Questions & Answers] note9_lavender:
Good morning, dear respective XDA community members!

Yesterday I have encountered with complete misfortune. I really hope on your expertise and expert knowledge in that issue. Appreciate your help and thank you very much in advance!

I have a Nokia 8.3 5G as my main working smartphone which I cherish as the apple of one's eye. I have headaches from PWM and can't use Samsung phones because of PWM and I need Android 10 as I have some work related apps which works only with Android 10.

So from the date of purchase my phone was complete brand new with Android 10 (Build number 00WW_1_110_RU) and (Android security patch level September 1, 2020) out of the box. I did not done any manual downloads and update of Android security patch level and neither Android updates to 11, 12. But last few months I started to receive irritating splashing system window with following text “Your system is out of date for 273 days, update & restart now”. While launching Opera browser the click on it's icon matched with the time of appearing that update window and phone pushed “restarting now” text with rotating circle. I fully understood that I was done here and started to press and hold power button to somehow block the execution of update but phone displayed standard boot up logo "Powered by Android" with green Android logo instead of standard white. I hold power button again and phone switched off. On the next attempt to boot it the "Powered by Android" logo remained with green Android. I understood that I now can't influence on it's update process. Now my phone with Android 12 (Build number 00WW_3_380_RU) and (Android security patch level: April 1, 2022).

I totally dislike Android 12, interface design not suits me, performance of the phone drastically decreased. And those specific software which I used for work only works on Android 10, developer of them would not make it to work with Android 12 due to platform limitations.

I never done any manual updates of Android, and Android security patch levels, strange that security patch updated by itself without my command.

There are no any information in the internet regarding of downgrading the Nokia 8.3 5G from Android 12 to Android 10. The only information I was able to find is how to downgrade Nokia 2.2 from Android 10 to Android 9, using boot slot change method, available here: https://www.techmesto.com/downgrade-nokia-2-2-from-android-10-to-android-9-pie/ I am not sure whether this tutorial applicable for Nokia 8.3 5G. I did not tried anything yet as now I am afraid to get a brick.

I consider actions of Nokia by rolling such splashing window with update without confirmation mechanism as criminal. Every person encountered with that must make Nokia liable and get case to court. Last time I encountered with such nasty situation was with iPad, I do not remember which generation it was as it happened while ago, but same situation with splashing update window happened when I tried to open Safari browser. And I was not able to get downgrade as Apple stopped signing iOS I needed.

Such actions are illegal as those Android updates are completely affects the performance. On Android 10 I had about 5.2 GB after boot and about 3.2 - 3.5 GB during work of free RAM. Now I have 4.2 GB of RAM after boot and only 2.2 GB during work. That's horrible as I lost of 1.3 GB of RAM, Android 12 decreased performance of my phone completely. Apple does same with their new iOS for older devices.

Even Samsung does not do such illegal actions, my father have old Samsung Galaxy S8 with stock Android 8 for years, he accidentally clicks every time on some system settings and asks me to revert them, but even there Samsung not uses any splash window with update, only Android update message I see from his phone is in notifications, but you have need to pass good amount of windows with confirmations in order to get Android update, so even unexperienced users are safe from accidental Android update.

It's a shame for Nokia. I would never buy anything from them again. Such technique with splash window is done by fake hacker apps and their swindler developers, every time you see some commercial such windows are appearing "Do you want to close advertisement?", but instead of closing it forces to redirect on downloading link of some virus APK or opening Google Play with malicious application.

Could you please say what I must do in order to safely downgrade my phone back to Android 10. I do not need the Root as I need to use NFC payment options of Google Wallet.

I can’t work now as applications I used for work only works with Android 10.

Thank you very much in advance for your expertise in this issue! Appreciate and grateful for your help.