Some apps (such as Huawei Health) are installed on your device during the initial boot. They can, however, be uninstalled, and there's no obvious way to get them back. Here's how you do it! The APKs live in the /cust directory on your device. You can either pull them (using ADB, e.g. 'adb pull /cust/preinstalled/public/app/') or use a file explorer app to browse to the same directory and click the APK you want to install. Easy! :) P