do you realize that you have just admitted that the Tivo is perfectly
fine and legal?
because you can solder off the ROM from the Tivo and can put in a new
ROM with another bootloader that does not check the SHA1 key. Tivo puts
no restrictions on you to obtain a ROM and a ROM burner and do this work
yourself. (they dont help you either, but you just conceded in another
thread that the hardware maker does not have to go out on his way to
help you in your software modification efforts.)