How to change DB file for OpenStreetMap for iOS?

I开发者_运维知识库 have one problem with OpenStreetMap (OSM). I try to change the DB file in realtime and try to show the map of the one country. So my workflow:

1. Remove MapView object, clean delegate and data.
2. Copy db file to the original file (MapOpenStreetMap.sqlite).
3. Create new MapView object.

No success. I can't get tiles from new db file for the map. Only after restart the application. Any suggestions? Thanks!