MMC inside N900 gets mounted by /usr/sbin/mmc-mount or something like this. Don't be surprised that it starts fsck.vfat -a /dev/mmcblk0p1 However, if your memory is seriously wrong, it will not get repaired by this. Try to run, as root: umount /dev/mmcblk0p1 fsck.vfat -avl /dev/mmcblk0p1 To see which files are wrong. If you want to repair it, run fsck to completition. You may need to keep charging N900, to prevent shutdown-during fsck. Since for me shutdown-during-fsck was inevitable, I used switch -w to cure the filesystem. After the filesystem gets repaired, reboot, and it should auto-mount. It may take several minutes, though, to assure itself that the filesystem is fine. Best wishes.