Reference Vivo Y91! (1817) qualcom password unlocktool.

[Gadgetgeek]

Problem/issue: security/password
Software: unlocktool
Hardware: by testpoint

Procedure:
Remove back cover
Remove the metal locket
Open software (run unlocktool)
Select qualcom tab
Thick on server button
Select brand
Select model (y91)
Thick factory setting
Then connect tp
Then wait software to complete
Then start the phone.
Factory or recovery mode auto boot.
Select factory setting and reboot.
Then set up device.
Assemble
Then dont forget the payment.
Wag na mag wipe data. Para di maghang.