New unit and the 64 mb card is too small to store maps for an approaching trip. Topo data appeared as expected from MapSource Topo on the 64mb card. I guess I got greedy and purchased a 1 GB SanDisk card. I probably only used about a third of the card's memory. Topo data is no longer visible, even after downloading the map sets twice.
Is 1 GB too large? How large of a memory card will this unit handle?
Thanks

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