Battery optimizers allow mobile devices to extend their batteries but at the expense of performance, notifications and even shutting down background services on your child's device. Boomerang in Child Mode needs to run as a background service and can get turned off by these very aggressive battery optimizers.
Huawei also uses its own customized Android version named EMUI. This is another version of Android with little documentation and many non-standard background operations that conflict with background services such as Boomerang. Here are a few solutions to try on your child's Huawei device.
Adjust your settings:
- Phone settings > Advanced Settings > Battery manager > Power plan is set to Performance
- Phone Settings > Advanced Settings > Battery Manager > Protected apps – check for your app as Protected
- Phone Settings > Apps > Your app > Battery > Power-intensive prompt [x] and Keep running after screen off [x]
- Phone settings > Apps > Advanced (At the bottom) > Ignore optimisations > Press Allowed > All apps > Find your app on the list and set to Allow
Huawei P9 Plus:
- Phone settings > Apps > Settings > Special access > Ignore battery optimisation > select allow for your app.
- Phone settings > Battery > App launch and then set your app to “Manage manually” and make sure everything is turned on.
Huawei Honor 9 Lite:
- Phone settings > Battery > Launch and then set your app to “Manage manually” and make sure everything is turned on.
Tips from https://dontkillmyapp.com/huawei