Does the bike have a "lighter socket"? They used to have sort of a trickle charger that plugged into a lighter socket that kept a low amp 12v supply in the electrical system while the battery was disconnected. I think that's still how they do it.
The following works on my RM. Open your saved routes. On the bottom are two icons (phone & USB). To save to a flash drive, Insert the drive and click on the USB and you will be asked if you want to export this route. Indian favors drives formatted FAT32. You can also export to your phone - follow the on screen prompts. I don't think there is a way to select all routes so you may have to do this separately for each favorites.