I used the command mfsbackup -Tao - /dev/hdc | mfsrestore -r 4 -s 127 -xzpi /dev/hdb to upgrade and expand from an 80GB Maxtor drive to a 500GB Seagate drive for my Pioneer 810H unit. The command completed, added new partitions 14 & 15 and stated that I had 500+ hours of recording time. I installed the new drive in my TIVO and it works fine, but still only reports 89 hours of recording time in the System Information screen. (All existing recordings are present and all season passes transferred OK.)

mfsinfo reports the following:
/dev/hdb10 MFS Partition Size: 256MiB
/dev/hdb11 MFS Partition Size: 33887MiB
/dev/hdb12 MFS Partition Size: 256MiB
/dev/hdb13 MFS Partition Size: 42991MiB
/dev/hdb14 MFS Partition Size: 0MiB
/dev/hdb15 MFS Partition Size: 398896MiB
Total MFS volume size : 476287MiB
Estimated hours in a standalone TiVo: 582

The WeaKnees instructions for this unit mention "that not all 810H images can be upgraded. For some reason, some 810H images expand and others don't." Am I out of luck?