Not useful in this situation, but a friend of mine recently convinced me to buy an offline mapping app and all the maps for my country. Apparently, he was able

Not useful in this situation, but a friend of mine recently convinced me to buy an offline mapping app and all the maps for my country. Apparently, he was able to get out of trouble with plenty of battery to spare by turning off cell/wifi/bluetooth and just relying the app and the built-in GPS.