St Malo 2 Nice navigation

So my countdown timer tells me I have 43 days left until I start my St Malo 2 Nice solo trike ride for Bowel Cancer UK. I have been using the Karoo cycle computer which has fantastic screen for mapping and routes but has had the odd hiccups in software updates. As it’s my main navigation system I think I may need a back up? Maybe I can have the phone as a back up and or print cue sheets just in case .... solo ride nerves 😂