GrapheneOS – When an App Is Slow

After a year of using GrapheneOS on a Pixel 8, everything worked well except one mapping app: OpenStreetMap for Android (Osmand) ran noticeably slower than on other Android phones. That slowdown prompted a search for alternatives and led to finding CoMaps, which satisfies most needs, but there remained interest in keeping Osmand usable occasionally. Investigation revealed the performance problem is tied to GrapheneOS’s hardened memory allocator, which adds nontrivial overhead for apps that constantly allocate and free memory - exactly the pattern produced when scrolling and loading map tiles.

The practical remedy is to disable the hardened allocator for Osmand alone via the per-app Exploit protection settings: long-press the app icon, tap App info, open Exploit protection and turn off the hardened memory allocator, then restart the app. Doing this restores Osmand’s normal responsiveness. That change reduces one layer of hardening, so it’s a security trade-off; given that Osmand primarily uses offline map data and only occasionally updates from the internet, the author considers the speed gain worth the modest risk.