On FAT12, the current FAT driver recognizes 0xff8-0xfff as EOF, and it
writes in 0xff8 as EOF.  This is right behavior.  However, the firmware
of some MP3-Players recognize only 0xfff (standard EOF which Micorsoft
uses) as EOF.

So, we write 0xfff instead of 0xff8 as EOF, until the reason we need
values other than standard EOF is found.

[Randy Dunlap, I appreciate your help.]