Centril

1. Download [terminal emulator] from playstore.
2. Open [terminal emulator] and execute the following: `am start --user 0 -n com.android.settings/.SecuritySettings`. This will launch the Security Settings which Philips has hidden.
3. Scroll down and: Enable unknown sources.
4. Profit.

<!-- references -->
[terminal emulator]: https://play.google.com/store/apps/details?id=jackpal.androidterm