I have been using two transcend 8 GB cards successfully since the latest firmware and subsequent SDHC patch came out. Using the file manager I tried to remove a file and the action failed, saying the device was read only. So, at some point this has gone south. I can still read things from the disk, but just can't make changes. I don't think that I have removed it uncleanly from the PC connection, but I guess it might be possible. Would that render the disk read only? Regardless, is there a way to make this writeable again? I can recreate all the files that are on it, so should I reformat it? If so, I would have to do that in a PC correct?

All sd cards have a toggle switch on them to write protect them... Have you checked that yet? You may have accidentally toggled it to read only mode.

Just a thought.

The read-only switch isn't respected by the N800 (it's a hardware feature to detect the position of the switch, which isn't implemented by Nokia).

Bug #1204 is trying to get to the bottom of this problem... try mounting the card in Windows to see if the filesystem can be fixed.

This happened to me this week with a transcend 8gb class 6 card. I backed it up to the PC and reformatted it from the PC. This has fixed it.

Edit: If you format it from the N800 you only get 2Gb.

As I side note, I found the problem because Mplayer was locking up when started.