navionics updated itself going from really usable to not.
It now has the same colour as the land on the waters her the land.
Anyone know why?

Looks to me that the update didn't complete, I don't bother with the updates every time they come up, I usually wait till I've got good coverage and more than enough gigs to use. General thing to do is close all the apps that are running shut down the device, wait a few minutes and turn it back on again, and cross your fingers. Good luck