There are many memory technologies competing with flash. Find out what the options are and how they work.
As opposed to the FRAM, an MRAM actually does use magnetism to store bits. This makes some people worry that bits will be disturbed by external magnetic fields, but these bits are flipped by energy that is applied in very close proximity to the magnet, so the local field is extraordinarily dense compared to most externally applied fields. In other words, although you could cause bits to by applying an external magnetic field, that field would need to be extremely strong, so it would take a big effort to cause any trouble.