DB concurrency problem

OSN is using threads in order to simultaneously:
- download tiles (5 threads in [1]OpenStreetMapTileDownloader.getRemoteImageAsync() ),
- load map tiles (2 threads in [2]OpenStreetMapTileFilesystemProvider.loadMapTileToMemCacheAsync() ).

SQLite allows simultaneous SELECT in its database but not UPDATE.
That's why we have this kind of error sometimes:
<pre>
E/Database(24031): Failure 5 (database is locked) on 0xf1ee48 when executing 'UPDATE t_fscache SET countused = countused + 1 , used_timestamp = datetime('now') WHERE name_id = '/sdcard/org.opensatnav/tiles/tile.openstreetmap.org/18/xxxxxx/xxxxx.png.osn''
W/dalvikvm(24031): threadid=363: thread exiting with uncaught exception (group=0x4001b178)
I/global (24031): Default buffer size used in BufferedWriter constructor. It would be better to be explicit if an 8k-char buffer is required.
E/AndroidRuntime(24031): Uncaught handler: thread pool-61-thread-1 exiting due to uncaught exception
E/AndroidRuntime(24031): android.database.sqlite.SQLiteException: database is locked: UPDATE t_fscache SET countused = countused + 1 , used_timestamp = datetime('now') WHERE name_id = '/sdcard/org.opensatnav/tiles/tile.openstreetmap.org/18/xxxxxx/xxxxx.png.osn'
E/AndroidRuntime(24031): at android.database.sqlite.SQLiteDatabase.native_execSQL(Native Method)
E/AndroidRuntime(24031): at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1610)
E/AndroidRuntime(24031): at org.andnav.osm.views.util.OpenStreetMapTileFilesystemProvider$OpenStreetMapTileFilesystemProviderDataBase.incrementUse(OpenStreetMapTileFilesystemProvider.java:403)
E/AndroidRuntime(24031): at org.andnav.osm.views.util.OpenStreetMapTileFilesystemProvider$1.run(OpenStreetMapTileFilesystemProvider.java:179)
E/AndroidRuntime(24031): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
E/AndroidRuntime(24031): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
E/AndroidRuntime(24031): at java.lang.Thread.run(Thread.java:1096)
</pre>

Both threads are calling OpenStreetMapTileFilesystemProvider.incrementUse() which executes an UPDATE.

How to keep the treads without perturbing SQLite?