According to a report from The Wall Street Journal, Microsoft will be investing $70 million in Cyanogen, Inc., the Android ROM builder. The report says that $70 million would make Microsoft a “minority investor” in a round of financing that values Cyanogen in the “high hundreds of millions.”

Cyanogen takes the Android source code and modifies it, adding more features and porting it to other devices. It has also started supplying Android builds directly to OEMs (like the OnePlus One), which ship the software on devices instead of stock Android. Last week during a talk in San Francisco, Cyanogen’s CEO said the company’s goal was to “take Android away from Google.” It wants to replace the Google Play ecosystem with apps of its own, the same way that Amazon uses the Android Open Source Project for its Kindle Fire products but adds its own app and content stores.

A Microsoft investment in the company would be the latest in Redmond’s ironic ties to Android. Microsoft is thought to make more from Android patent licensing fees than it does from Windows Phone, and through its purchase of Nokia, the company even briefly sold Android-based handsets. Now, according to the Journal, Microsoft will become an investor in a company that sells an Android distribution.

Cyanogen says 50 million people are using its modified version of Android, which would put it at five percent of the one billion active users that Google touts. Nearly all of those Cyanogen users are still using Google Play, though. The real challenge for the company will be convincing its hardcore Android user base to dump Google Play and use the Cyanogen app store.