update to the latest Firmware and perform a factory reset in recovery after that.
wipe data/factory reset in recovery (this will delete your data/settings):
- Power off and then press Power and Volume-up together for around 10 Seconds
- be sure that the little arrow point on recovery (select with volume up, enter with volume down)
- Then the open android with red triangle+"no command" is shown - press Power and Volume up together again
- Select Wipe data/factory reset with volume keys, confirm with power
- After factory reset select reboot system now
Please report if this solved your issue or not.
someone has the blackview android 6.0 firmware link to test it until it solves android 7.0 and its mortale stops