Ehhh, technically but its hard for them to tell if your able to switch back before turning it in. And if it doesn't boot then well... It's not going to be much of an issue then. Also it is a bit legally grey if companies can void you warrenty solely for installing a custom ROM.
They provide, or at least used to provide, ROMs of both Oxygen and Hydrogen OSes to flash at your leisure. Not 100% what the deal is in the new OPPO-ish world.
Ehhh, technically but its hard for them to tell if your able to switch back before turning it in. And if it doesn't boot then well... It's not going to be much of an issue then. Also it is a bit legally grey if companies can void you warrenty solely for installing a custom ROM.
I know with OnePlus, they wipe your phone right out the gate when you send it in for repairs. I've had mine fixed twice and never had an issue.
Oneplus allows it in its warranty I believe
They provide, or at least used to provide, ROMs of both Oxygen and Hydrogen OSes to flash at your leisure. Not 100% what the deal is in the new OPPO-ish world.