its possible to change rom?

[Geo115]

I have note 20 ultra sm-n9860 and I want to change  to official sm-n986U1 rom.

[shouldangelsdie]

samsung pay says Hong Kong because your device was for china's market, this means you can flash roms that are for sd versions not for exynos, DO NOT FLASH Greece roms or European. try usa or other countries that use snapdragon versions.

[shouldangelsdie]

and I'm afraid usa don't work either, only China, Hong Kong and Taiwan see the link

https://www.sammobile.com/samsung/galaxy-note-20-ultra-5g/firmware/#SM-N9860

[Geo115]

thanks a lot for your help!
"question" what happen if I change to USA rom unofficial?
the phone is working correctly?