Copying to usb flash drive corrupts files

[Łukasz Sromek]

Hello.

I asked this question on bsdforums.org, but I got no answer. I guess
this list is a better place to post problems like this.

When I copy mp3s from hard drive to usb stick they become corrupted.

lukasz ~% mount /mnt/usb
lukasz ~% cp file.mp3 /mnt/usb
lukasz ~% diff file.mp3 /mnt/usb/file.mp3
lukasz ~% umount /mnt/usb
lukasz ~% mount /mnt/usb
lukasz ~% diff file.mp3 /mnt/usb/file.mp3
Files file.mp3 and /mnt/usb/file.mp3 differ

If I set sync option in fstab:

/dev/da0 /mnt/usb msdosfs rw,noauto,sync 0 0

Then files are copied correctly, but very slowly, when buffer size is
low. Midnight Commander uses 8k buffers, so I get about 20kB/s which
is unacceptable.

I'm using FreeBSD 7.0-RC2.

Could you help me with this issue?