If your OPPO F1s A1601 shows a (FRP β Factory Reset Protection) after a hard reset, you will need to bypass the Google account verification.
: When the OPPO logo appears, release the Power button but keep holding Volume Down until the language menu pops up. withi riset pen kha reim tn cak rongngan OPPO F1s A1601
: Release the buttons once the OPPO logo appears on the screen. If your OPPO F1s A1601 shows a (FRP