As a word of caution, I carried both a Nokia phone with the Nokia Maps application loaded and a handheld Garmin on my last pilrimage (St Olav's Way). Like the Camino, this is sufficiently well marked so that one doesn't rely on these aids, but I thought that Nokia Maps would be good for detailed navigation in towns and the like.
There were two problems with the Nokia. First, it took ages to find my location if I was any distance from a road. I find this here in Australia too. It seems to me that it is highly optimised for vehicle navigation, and not for walking. In a couple of places, I just gave up waiting for it, and relied on the Open Street Map data on my Garmin.
Second, it always wanted to establish a data connection to download updates or additional data. This was partly my fault, because when I could find a wifi link and upload data, I would forget to turn the internet connection toggle back off again. Nonetheless, it seems to default to trying for a data connection over using the available data.
Regards