Setar bordas customizadas no botão...

sampleViewController.m

UIBezierPath *shapePathFB = [UIBezierPath bezierPathWithRoundedRect:self.btnSampleOutlet.bounds
                                                    byRoundingCorners:UIRectCornerTopRight | UIRectCornerBottomRight
                                                          cornerRadii:CGSizeMake(7.0, 7.0)];
    
    CAShapeLayer *shapeLayerFB = [CAShapeLayer layer];
    shapeLayerFB.frame = self.btnSampleOutlet.bounds; // Why set bounds? My btn has bounds already...
    shapeLayerFB.path = shapePathFB.CGPath;
    shapeLayerFB.fillColor = [UIColor clearColor].CGColor;
    shapeLayerFB.strokeColor = [UIColor blackColor].CGColor;
    shapeLayerFB.lineWidth = 1;
    [self.btnSampleOutlet.layer addSublayer:shapeLayerFB];