The majority of Huawei phones have a feature called “Maintenance Mode”.
Maintenance mode is designed to protect your photos, contacts, messages, and other personal data during the repair process. When Maintenance mode is enabled, your personal data is completely isolated and cannot be viewed, and the prompt "please contact the owner for permission to use this feature" will be displayed if the user tries to access some apps such as Messaging.
Huawei technicians require certain access to a device for diagnosis reasons, so we highly recommend you enable maintenance mode before booking a repair with us.
How to enable and disable 'Maintenance Mode'
Enable Maintenance mode
If you would like to have complete control over access to your personal data before sending your device for repair, enable Maintenance mode by following the steps below:
Open Support (or HiCare) App.
Touch Maintenance mode by going to Quick services.
Touch Enable and select Restart to enable Maintenance mode.
If you have never set a lock screen password before, the system will provide for step-by-step instructions for how to do so.
Disable Maintenance mode
After your device has been repaired, you can disable Maintenance mode by following the steps below:
Swipe down from the status bar to open the notification panel.
Touch the Maintenance mode prompt.
Enter your password to disable Maintenance mode.