How to solve Android’s “bluetooth has stopped” error (on LG G2, and require root)

Recently, I visited Mobile World Congress 2015 in Barcelona held by GSMA. GSMA created an application specific to this event to enrich the experience of the visitors.

One of the features of the application was indoor location-based service. They used bluetooth proximity approach to detect the current location of users. The application would detect a lot of bluetooth devices around the event, and cached them in local memory.

While the objective of this approach was very helpful, unfortunately there is a bug in Android that will cause bluetooth service not working properly. After storing up to 1990 bluetooth devices, the Android handheld won’t be able to add/pair new bluetooth device.

Initially I didn’t know why my bluetooth service in my LG G2 acted strangely (occasional error shown like picture above). After doing some searching, I came to know that this error was caused by the previous bug explained.

Since I had root access in my LG G2, the solution was very easy.

1. Install root explorer (or equivalent application)

2. Browse to file /data/misc/bluedroid/bt_config.xml

3. Backup the original file

4. Copy file to your sdcard, so that you can copy to your PC and edit

5. Open the bt_config.xml with text editor, search <N2 Tag=”remote”>. The content reside in this tag, are bluetooth devices being cached.

6. If you see in my example, the content was exactly 1990 entries

7. Delete most of the content under <N2 Tag=”remote”> and </N2>, leaving only your bluetooth devices

8. Save, and copy back to /data/misc/bluedroid using root explorer.

9. Restart your handset (changes won’t take effect until you do this)