I too have had some issues with my sd cards. the following is what I posted into the "metecrawler" posts but I think that it has some bearing here as well. I have yet to destroy any cards but I think that I may have come close. here is my post:

"I am a newbe, but I have been following these and all other posts that have to do with battery life and sd card failures. I have had my n800 for about 5 months now. I have been using 2 [two] 2gig sansdisk sd cards continuously filling up, moving around, and swapping out files including movies, pictures, pdfs, and a lot of use with Mam Mapper. Until the os update that is. After the update I wuikly noticed that battery life tanked. Like the above posts..very quickly. I started to play around with the sd cards...ie: empty, full, partial etc... it did not matter. I found too that I began to have a great deal of apps that would hang forcing reboot after reboot. I have finally just put back in the nokia micro sd that the n800 came with. I have no card in the external slot. Battery life is back to what it was when new. As soon as I put another card in the external or internal slot...I immediatly lose hald the battery and apps [does not matter which ones] begin to hang. none of this happened before the os update. I have not and will not try a larger size sd card until this is fully resolved. I would appreciate any input as well. I am not a linux guy or programmer of any type. Just a consumer who thinks the n800 is an incredible little piece of tech.."

i've managed to exchange my fried card to working one twice, at the third time i finally made a refund

Has anyone had a problem that they could access their SD card but couldn't write from the n800? I have a 1gb card that I can read/write from an external reader and from my computer via the usb cable to the n800, but when I try to save anything - it says "File is read only" - anyone have this frustrating issue?

I've tried changing switching the cards from the inside slot to the outside and vice versa with no luck - the card itself seems to be set at read only.

I've also tried chmod -R 777 /media/mmc1
but it comes back as "chmod: mmc1: Read-only file system".

Anyone have ideas on this? I don't know how or when exactly this happened.

BTW, I just searched google and found this. The forum's own search didn't yeild anything for me on that.

BTW, per that thread, I formatted the card in my external reader under winxp and it's now behaving correctly - thankfully.

Now I've fried my 2nd card. The first was a 512mb... no big deal. This morning I was watching a dvd on my n800 which was accessing my 8gb class 6 sdhc, and then everything froze. I had to reboot by taking the battery out, and when it rebooted, drive corrupted. Tried reading from my PC card reader; gave me a device I/O error. Even tried to format with several disk utils, no luck. $55 down the drain after only 1 month of use. Brand was Adata. This is definitely a prolific problem and it is causing us consumers to be the guinea pigs. How about Nokia allows us to send them the fried cards and they send back replacements of the same size??? Yeah, right??? Maybe they will always be the red headed step child of the tablet scene because of problems like this that they will do nothing about.

They probably have a legal way out of this. No luck there.
I just burned my first one this morning and i will not stick a high-capacity SD card in the external slot anymore until someone finds a solution to the problem.
I think in Bugzilla Nokia is looking in the wrong places. Mine was burned while walking in the street. Nothing about transferring files, no connectivity whatsoever. And since it only seems to happen in the external slot i get the feeling that our devices are faulty.
How about that, Nokia? What about replacing the faulty N800's for ones that don't corrupt SD cards in the external slot? Ones that do have the physical connector/slot properly done.

Ton.

"It is just best in general to manage bug reporting in a single location. That's just good practice. Bugzilla is the place.

To those who question why they should be so burdened, my simple answer is: welcome to Linux."

Good point, but the big picture is that it's Nokia that has the problem with SDHC cards, and Nokia shoudl look for wherever it can find clues to solve its problem. This thread can't be good for Nokia; the people reporting aren't haters of the N800 or people with grudges; they are just reporting their experiences.

geneven, that's exactly what Nokia is doing. Some are making the mistake of thinking absence of evidence is evidence of absence. But the developers are indeed trying hard to reproduce the problems reported in the wild. As I already noted, though, there are many, MANY variables and only a sober, methodical investigation will identify cause(s). This forum is good for venting. Bugzilla is good for the investigation. So both serve a valid, distinct purpose.

And the developers are well aware of what negative publicity does. These guys are close to the product, too, and take pride in it doing well.

Dead man walking here, boss!

Well, go ahead and add my name to the list. My trusty little 2GB PNY SD just bit the big one. Device couldn't see files on the card and it was greyed out in the File Manager. This had happened a couple of times before but a reformat brought it back both times. Tried to access some videos with Canola this evening and it had disappeared again, only this time it won't come back. Tried reformatting it with the NIT and on my computer with a card reader under both Mac OS X and Win XP but still no joy. Haven't tried on my Linux box yet, but I'm not really in the mood to do any more troubleshooting right at the moment. I believe this may in fact be what is referred to as the proverbial last straw. Haven't decided yet whether I'm just going to stick it in a drawer for now and try again when Chinook arrives, or just return it for a refund while I still have time and grab an iPaq 210. Probably should sleep on it and make a decision when I'm in a more objective frame of mind.