start.elf	/ fixup.dat	- normal
start_x.elf	/ fixup_x.dat	- with extra feature including camera (start_x=1 in config.txt)
start_cd.elf	/ fixup_cd.dat	- cut-down to minimum gpu set 16M
start_db.elf	/ fixup_db.dat	- debug (start_debug=1 in config.txt)
