I had problems initially with my two 8GB SDHC cards, using the latest firmware. Here was my solution:

1.) Do a fresh flash to the latest firmware.
2.) Flash to the Kernel listed in the following thread: http://www.internettablettalk.com/fo...t=kernel+flash
3.) Power on without any cards in the device.
4.) Power off, put cards into the device, power up the device with the cards inside.

If you're willing to backup/reinstall all of your stuff to salvage this card, it might be worth it. When this happened to me, one of my cards claimed that the partition had been sized outside it's limitations, and I couldn't fix it with fdisk or parted. For me, the important part was to give it a power cycle without any cards, and then let it load up with both cards in there.

Admittedly, I was not too pleased with this solution, and I wanted to tell Nokia that on the retail box, under "System Requirements" it should say "Magic." But, I was able to get both cards working, and haven't had any issues since then. Although, I do not, ever, try to hot-swap, or remove them.