Update system functionality not working

[Ruben Barron]

Hi All,

I'm new in this forum and in this android world. I have a Huawei mate 9, time ago I used Firmware Finder app to download and install a new firmware for my smartphone, after that, when restarting or turning on it, I receive a message that my phone has been unlocked and can't be trusted, also I have lost the functionality to change themes and the update system functionality. I have been trying to find a solution to have my update system functionality available again.

can you please help me with the instructions to fix this?

smartphone details:
Model: BLL-L23
Compilation: NRD90M test-keys
EMUI: 5.0.1
Android: 7.0

Any help will be appreciated