I've inherited an Axon ZTE and want to use it for a while to see if I want to move away from my iPhone. I did a factory reset and I've started to install my various apps. When I tried to run Google Pay, it won't install as my phone is either Rooted or running a custom ROM. I downloaded an app called 'Root Checker' and it says the phone is not rooted and so I assume the phone has a custom ROM (in fact, I'm sure this is the issue as the previous owner was a member of this forum and liked creating custom ROMs).
So - is there a way to go back to the vanila / manufacturer ROM?
I've had Android phones before, but not for about 6 years - so any help would be really appreciated.