I just bought the n800 recently, and I am having trouble with the external memory card slot. I bought a 4 gig SD card to put in the internal memory card slot and it works flawlessly. No card I try works in the external slot.
I tried to use a micro SD card in an adapter first, but that didn't work. So I tried a regular SD which also didn't work.
Is there something that i have to activate to make it work? or maybe some way to check and see if somehow its disabled? Any thoughts would be helpful.

Check this, maybe can be of help...