Android Oreo was a theming wonderland. We could use Substratum to theme the entire operating system without even having to root our device. That sounds wonderful, doesn’t it?
Unfortunately, this doesn’t work in Android P and Google confirmed that it never will. In the Google Issue Tracker, the company marked the issue of Substratum not working in Android P as “Won’t Fix (Intended Behavior).”
“We appreciate the feedback and would like to share some background information and clarifications.
The Overlay Manager Service (OMS) is intended for device manufacturer’s use. OMS, in its current form, is not designed to be a generic theming feature — more design considerations will need to be put into it in order to uphold Android platform’s security and product standards for users. Accordingly, OMS has never been advocated as a public developer feature.
Earlier this year a security patch (CVE-2017-13263) was released to OEMs for Android Oreo devices. The patch restricts the installation of overlays to pre-installed or system-signed apps, in response to a legitimate security issue raised in Android Oreo. Android P also includes this critical security patch, so it restricts overlays in the same way as does Android Oreo.
We understand that custom theming is an important capability for some users. We will take your feedback into consideration with any future work in this area.”
As sad as this is, it’s an expected move by Google. The company has worked hard to close every single security hole on the platform, and security is a very important topic in the current day world.
As much as it makes sense for Google to disable third party overlays, it’s simply a loss for the modding community.