ZTE Kis III KIS 3 hard reset
You can reset your ZTE KIS 3 V790 device's password: Turn off your phone, then turn it on. Select emergency dial. Key in *983*987# in emergency dial-up pad. It will restore factory settings and your personal data will be erased.or hard reset using keys:
1. Turn ZTE KIS 3 off.
2. Press and hold volume up + power on and
3. choose wipe data/factory reset using Volume down (power to confirm ).
4. Select Yes -- delete all user data.
5. Select Reboot system now.
Reset unlock ZTE KIS 3 password
1. From the Home screen, press the Menu Key and touch Settings.
2 Touch the Backup
4 Touch Factory data reset.
5 Touch Reset phone.
6 Touch Erase everything.
ZTE Kis III KIS 3 firmware upgradeDownload sdcard.zip from official website here
Copy it on your SD card root directory
1. Turn off the phone. Be sure the battery is minimum 50% charged.
2. Power on the phone while pressing the Volume UP key.
3. Release the keys when the system recovery menu appeares.
4. Select "Apply update from sdcard" using Volume down key confirm with power.
5. Wait until the update finish.
6. After all done select Reboot system now to reboot the phone.