I tried factory resetting a Samsung Galaxy S6. To my surprise, it left Android 7.0 on it, and didn't reset it to Android 5, which is what was originally installed from the factory.
Is this normal? Is there a way to make factory reset force the phone to return to the original factory ROM?
For those curious as to why I would want to return to the original factory ROM, it's because when I take photos (even after a Factory Reset), I sometimes get a "Server Error". I'm thinking that perhaps a bad ROM update is causing this issue, as I've already had the camera replaced by Samsung.
So I was interested in returning to the original factory ROM, and then upgrading it again to the latest version.