restore failed backup target not large enough to hold entire backup by itself

hi there. i have a friend's toshiba sd-h400 (circa 2004) tivo with a failed hard drive (i have an identical one).

I've done this before a number of times for other friends over the years; i have an older pc in garage all set to go, it boots up PTVupgrade LBA48 off of a CD (linux)...

i got my backup image mounted just fine (for simplicity lets say it's a backup of the original Maxtor 80G that came with the unit; it was never hacked or whatever)...



when i do with the new/target drive as hdd (secondary slave):

mfsrestore -s 127 -zpi /mnt/e/file.tiv /dev/hdd



all i get is an immediate error

restore failed backup target not large enough to hold entire backup by itself



Other attempts yield same error, e.g. i plugged in my origianl maxtor (that still works fine; it's been in a drawer for probably 10 years) and tried piping mfsback to mfsrestore and got same error.



I've tried two different target drives: a 160G and an 800G... i.e. both clearly larger than 80G



Help? How do i tell what mfs tools sees as the target drives size?