Hi, I am using yaffs2 on a 2.6.20. On the yaffs2 partition we mount a FAT fs with loopback. If we modify files in the FAT partition, umount it and do a sync. The data is lost after a unclean unmount. For example if yaffs2 partition is mount in /mnt and /mnt/media is a file containing a FAT fs. # mount /mnt/media /media/fat -o loop # cp /somefile /media/frame/somefile # umount /media/frame # sync <--- wait 10 seconds <--- power-off and power-on without umount # mount /mnt/media /media/fat -o loop # md5sum /somefile /media/frame/somefile 7fbf15f115bdbe93c3466b595a926b5e /somefile 6a7cfc972547b2385e97a4af3d854444 /media/frame/somefile There is no such problem if I write the file in the yaffs2 partition instead of FAT fs. Matthieu