Regarding your question: i would like to refer to my previous comments
in a very similar issue in our bug tracker: See:
https://code.google.com/p/mapsforge/issues/detail?id=206
Greetings,
Thilo
I don't know if OruxMaps has an option for that. But in the
AdvancedMapViewer there is a dedicated menu entry to select an XML file
from any readable folder in the local file system.
Greetings,
Thilo