I bought my galaxy s20 5G (in phone settings SM-G981U) outside USA and I live outside USA, so i can’t receive update by ota. My current firmware version is G981USQS1BTK2, Service provider is XAA/XAA/SPR. As I understood my phone is sprint unlocked. Should I uppate to 981U SPR or 981U1 XAA? And will my phone unlock remain after flashing?