If you have a screen lock (PIN, pattern, or password), enter it.
This is Factory Reset Protection . It's a security feature. You must enter the previous Google account (email and password) that was used on the phone before the reset. If you don't know it, you cannot bypass this legally. How to Hard Reset HUAWEI L21 P9 Lite
Open the Settings app.
Tap Backup & Reset .
A hard reset will erase ALL data on your phone, including contacts, photos, apps, messages, and accounts. It will return the phone to the exact state it was in when you first bought it. Back up your data before proceeding. If you have a screen lock (PIN, pattern,
Phone is stuck in a boot loop after reset. You must enter the previous Google account (email
If your Huawei P9 Lite L21 has a Google account on it, you must know that password after the reset, or the phone will lock itself. This is an anti-theft feature.