Early firmware didn't support SDHC cards only SD. So that might be your answer?

Check the About information in Control Panel for your firmware version.

Internal slot is picky.

My first one is kingston 8Gb class4.There is no problem to read and write data in interal and external slot. But the screen flashed every 3-4 second when I put it into internal slot and charge it.

Then I bought another one scandisk Utrl 2 4Gb clas 4 for the internal slot.It is no problem for now.

It said ,
Non-volatile solid-state; no moving parts maximizes battery power; data is not lost when power is turned off
Low battery consumption to maximize battery life in small portable devices
Operating shock rating of 2000Gs, equivalent to a 10' drop to the floor

I'm a new owner of an N800 and I bought 2 PQI 8gb cards from meritline (or was it supermediastore?). Anyway, they cost $35 each and I have had zero problems.

I was shopping recently ( end of December) for a place where I could buy a couple of different size cards for a good price. At the time it seemed to me that I could get a good price on one size at one place and then I had to go to yet another place to get a good price on another size. The other thing that seemed to be happening was that shipping seemed too expensive at most places. But I ended up finding a place called mwave.com that had good prices on most products and reasonable shipping costs. ( like the actual shipping costs rather than inflated.) So I paid $23 each for 4GB class 6 SDHC Transcend cards and $44 for an 8GB Transcend SDHC Class 6 card. I thought those were very good prices and the cards have been working fine.

Neil

For $90 plus shipping, 8Gb micro SD.

http://www.dz-tech.com/sandisk-8gb-m...age-p-951.html

This works using a micro-to-mini adapter in my n810 (the micro to mini is NOT included).

A-DATA 16GB class 6 - 59.99$ http://www.newegg.com/Product/Produc...82E16820211245

orderd them 2 weeks ago for 74.99

I just got an A-Data (from meritline) and it works in the N800 - I'm adding swap and ext2/3 partitions as I write this.

- ouch! got my two 16GB Adata class 6 cards at the US$59.99 price... they work great in my os2008 n800 - 32GB! w00t!

(of course, this time next year, a 16GB SDHC class 6 card will be US$29.95)

:-)