You can download all the maps with any computer here:

http://www.navicoretech.com/Consumer.../en_GB/tablet/

Here are awesomely detailed instructions
as to what to do with them.

http://www.internettablettalk.com/fo...5&postcount=11

Note that if you move the maps directory
from your N810 internal MMC2
to a card stuck in the external MMC1 slot,
the Map app will find them just fine.
That leaves you the internal 2gig MMC2 for KDE or whatever.