Use METAFLAC to edit Flac Tags
Install FLAC package, then metaflac will be present.
#root@moode:/mnt/SDCARD# metaflac --set-tag ARTIST="David Axelrod" holythursday.flac #root@moode:/mnt/SDCARD# metaflac --set-tag TITLE="Holy Thursday" holythursday.flac
#metaflac --list my_music.flac