Google is taking steps to curtail the proliferation of smartphones powered by open-source Android, which left unchecked could threaten Google’s revenue from the mobile operating system.

New data show that open-source Android devices, once thought to be prevalent only in China, may represent more than 30% of total Android smartphones in some key developing markets. That has implications for Google. The company wants more phones to run the advanced version of Android so that the software platform and experience can be more consistent for app developers and consumers. The advanced version also generates more revenue for Google, which mandates how many and where revenue-generating apps like Google Search must be placed on devices.

Google has been working on a new tactic to reduce the number of open-source phones: It is simplifying the process for lesser-known device makers to get certified to distribute the advanced version of Android, something that has been a barrier in the past, according to a person who has been involved in setting the strategy at Google.