Add me to the list. My 8GB Transcend SDHC card started off good, then had a few corrupted filenames, and progressed to where the N800 doesn't even recognize that the card is inserted. Here is my story...

Just got my N800 along with an 8GB Transcend SDHC card. The N800 shipped with the previous software release, so I didn't bother putting in the SDHC card initially. After playing around for a bit, went ahead and flashed the July 7th release. Put the 8GB card in the internal slot and an old 256MB card in the external slot.

Things were fine for a few hours - the 8GB card was recognized (FAT32) and could read/write to it fine. Even used MaemoMapper to download several thousand map files to that card. Then I tried to use the USB connection to transfer a big batch of map files from my Windows PC to the 8GB card. During the transfer, Windows started complaining. Canceled the transfer and used Windows file explorer to look around the card. Most directories/files were there, but there was one directory that had messed-up filenames (with symbols and other junk), when they should have been normally-named .JPG map files. Used the N800 file manager to look in that directory, and it also showed corrupted filenames.

Decided to re-format the 8GB card (mkfs.vfat). Seemed to work, but MaemoMapper complained about not being able to write. I'm sure I rebooted once or twice during that time, but MaemoMapper was never happy after that.

Then I got crazy and decided to try formatting it ext2. After finally getting the proper tools installed, I created the ext2 fs. Again seemed to work fine, but couldn't mount it. The ext2 kernel module wasn't installed, and I couldn't get it installed. So after going nowhere I decided to use sfdisk to re-create the partitions and start over. Still couldn't get ext2 to work. Then after one of many reboots, I lost the 8GB device file (/dev/mmcblk0). Tried the 8GB in the external slot and no device file there either. The old 256MB card is detected fine in both slots, but the 8GB no longer shows up.

Got and installed the patched kernel from http://intr.overt.org/blog/?p=54
to see if the extra debug output would be useful. Unfortunately it isn't very illuminating. Just says some commands timed out for the 8GB card.

Unfortunately I don't have an SDHC-compatible card reader for my Windows PC yet. So right now I'm stuck with an 8GB card that is unrecognized by my N800, which means I have no way of even trying anything else