Samsung devices require you to sign in with your Google account if you factory reset your phone. This is kind of ridiculous. It makes it a pain in the rear to resell your phone. Normally to sell your phone all you need to do is factory reset it. If you factory reset a new Samsung phone and then sell it the person who buys it from you won't be able to get into it without your Google account information. There is a way to bypass this. Rootjunky has put together a full guide showing you how to hack around this. This method works without a PC or an OTG flash drive. Just know that the method is pretty complicated. It requires you to log in to your wifi, unplug your router while your phone is checking for an update, reboot the phone, set a pattern lock, reboot the phone, access the camera, go to modes, access the download folder, install and use es file explorer to access rootjunky's download server, download an app, and run it! As I said earlier the method is pretty pain staking, but the outcome is oh so worth it! Check out the full video for the full proof method.