I have a 540080 Tivo

I used instantcake to get my tivo working after a HD crash. All is well but I would like to add another HD to the system now. I did a BlessTiVo and it still doesn't see the second drive.

Do I need to do a mfsadd -r 4 -x /dev/hdX /dev/hdZ with both drive and does it affect the good boot drive

The tivo is working fine now and I only want to add a second 500gig HD and now loose all the programs on the boot drive. Thanks