I also got the problem, that, when you download a big number of map tiles it takes very long (sometimes hours).

You should try first to download only one level. Choose a less detailed level like e.g. 12. The number of map tiles should be much smaller and download should run.

You can load map tiles using two other ways:

1. If you have planned a route, you can download only the map tiles around your route. But, you also have to take care, that you are not choosing to much levels or to detailed levels (for a big area).

2. Open Mappero and go to the zoom-level you like. When you now move the map on your screen, mappero loads the map-tiles for the areas that are shown. Of course you can use this way only for a small area or a short route.

I know, that this is not really a solution. It's just the way how I work around this problem. Hope I understood your problem right.