I believe the colonists disassembled their houses and traveled to the island of Croatoan where there was a Native American tribe member that they new. He and his tribe helped them survive living in the new world.
Before he left, John whit told the colonists to carve the name of where they were going in a tree. When he returned the word Croatoan was carved. In 1933, a Hurricane revealed European artifacts which proves they were there. John White believed they had gone there and wrote about it in his letter but neve traveled there.
No one had tried to reach the island of Croatoan for 80 years after John White. Before arriving in Roanoke, White spotted smoke and he thought it was Native Americans but he might have spotted his colony on Hatteras. I believe that John White placed the patch over the map in case he was captured during the war and forced to give Spain's plans to settle inland.