"Android and Users' Freedom" (2011) is stallman's analysis of the Android mobile operating system — nominally based on free software, but in practice falling significantly short of the free-software-definition's requirements. The essay is an application of stallman's analytical framework to a then-emerging and widely used platform, demonstrating that the presence of free software components does not make a system free in the relevant sense.
stallman's critique of Android is multidimensional. First, while the Linux kernel used in Android is free software, the majority of the applications that ship with Android devices are proprietary; users are expected and encouraged to install more from the Google Play store, which is a distribution channel for proprietary software. Second, device manufacturers routinely lock Android devices so that users cannot install modified versions of the operating system — a form of tivoization that makes the freedom to modify the software practically meaningless even where it legally exists. Third, the "Android" brand covers a range of practices that vary by manufacturer, making it impossible to treat "Android" as a single entity with a determinate freedom status.
The essay also notes the irony that Android popularized Linux-based computing enormously while simultaneously failing to advance software freedom in the ways that stallman and the gnu-project intended. Hundreds of millions of users now run Linux-kernel devices without being free software users in any meaningful sense.
stallman acknowledges the existence of remastered Android distributions like Replicant that attempt to create fully free Android systems, and endorses those efforts while maintaining that the mainstream Android ecosystem does not respect users' freedom.
The essay connects to tivoization, a concern that drove significant changes in gpl-v3 — particularly the anti-tivoization provisions that require hardware manufacturers to provide users with the means to run modified software on their devices. The Android situation exemplifies why those provisions were necessary.