* vtoy_reserved[2]: vtoy_chain_type 0:Linux 1:Windows 2:wimfile
* vtoy_reserved[3]: vtoy_iso_format 0:iso9660 1:udf
* vtoy_reserved[4]: vtoy_windows_cd_prompt
* vtoy_reserved[2]: vtoy_chain_type 0:Linux 1:Windows 2:wimfile
* vtoy_reserved[3]: vtoy_iso_format 0:iso9660 1:udf
* vtoy_reserved[4]: vtoy_windows_cd_prompt