Factory resetting an Android smartphone is not possible without the password from the owner. This feature was introduced by Google in Lollipop. The feature prevents the smartphone from being factory-reset by an unknown user or thief, unless he has the password from the original user.
However, an Android developer has managed to get past this security feature and factory reset the smartphone to gain access to the hardware. Although the data within is completely lost, the stolen smartphone can be operational once again.
Rootjunky, an Android developer, has posted a video that shows how the hack is simple, although it needs quite a few steps in order to be successful.
If the method is as easy as Rootjunky shows, then Google and Samsung are definitely, probably, on the case to patch the operating system and make sure their existing users are not at risk.
