When you visit a GApps download page, you will see multiple "variants" (also called packages). Here’s what each means for Android 5.1:
Since official OpenGapps builds for Android 5.1 are no longer updated, you have two safe options: gapps android 51
Warning: Avoid random “Gapps installer” APKs from unknown forums. Always download from XDA Developers threads or trusted GitHub repositories. When you visit a GApps download page, you
| Issue | Solution | | :--- | :--- | | "Unfortunately, Google Play Services has stopped" | The GApps package may be too large for your system partition. Try a smaller variant (nano or pico). | | Insufficient storage in system partition | Use a smaller GApps package (micro, nano, or pico). Remove unnecessary system apps. | | Setup Wizard keeps crashing | You likely rebooted between ROM and GApps. Re-wipe and flash ROM + GApps together. | | Google Play Store doesn't open | Clear data for Play Store and Play Services in Settings > Apps. | consider these alternatives:
This guide assumes you have already flashed a custom Android 5.1 ROM (like LineageOS 12.1).
If you want Google services without the bulk or privacy concerns, consider these alternatives: