Thread: Nuvi 1490LMT can't Update to NA 2014.20

No it's not too big. The real reason Garmin suggests certain limits for cards in nuvis is because having a lot of mapping data to load on start-up makes the boot time quite long and also there are limits as to the amount of map tiles [mapping segments] and indeed number of individual FID map image files which a unit can see. So using a very big card becomes quite pointless. I've used everything from 1GB microSD to 32GB mircoSDHC in 1xxx series without problem, and also a 64GB mircoSDXC reformatted to FAT32 but the big cards are just overkill.

Garmin devices can sometimes not see certain brands of cards, but it's really very rare. They only recommend Sandisk & Kingston for that reason, but most any card will work. Did you try hard reset/clear NV as i suggested?