No. Vivo S1 does not have the front camera flash. It has a display-screen flash.
It takes about 2 hours time to fully charge Vivo S1 battery from 0% to 100%. Please note that Vivo S1 comes with a huge battery capacity of 4500 mAh. Hence despite fast charging support, it takes a little more time to fully charge the phone.
Vivo S1 offers superb value for money. The mobile has almost everything which you should have in an ideal mobile. However, we feel that the following can be disadvantaged.
However, the phone does offer full HD video recording and also offers fast charging via MicroUSB port but we still feel that above could be of good help to users.
Yes, Vivo S1 has an in-display fingerprint scanner.