I'm posting a list of Tivos that cannot be hacked without a prom modification. DTivos need to be hacked to use their USB ports, standalones do not. Prom modding is not easy, but perhaps you can find a pro to do it for you. Unless you solder for a living and have the specialized tools to do it (special tips, solder wick, stereoscope, DATA I/O device), don't attempt to undertake this risky procedure yourself.
DirecTV Tivo R10
Tivo TCD540040
TiVo TCD540080
TiVo TCD540140
Humax T800
Humax DRT400
Humax DRT800
Humax T2500
Toshiba RS-TX20
Toshiba RS-TX60
TCD649080
TCD649180
DirecTV Tivo R10
Tivo TCD540040
TiVo TCD540080
TiVo TCD540140
Humax T800
Humax DRT400
Humax DRT800
Humax T2500
Toshiba RS-TX20
Toshiba RS-TX60
TCD649080
TCD649180