How is it stating that it's a combination of two drives? It does likely have two sets of partitions for media storage - could that be what you are seeing?

When the mfsadd command completes it reports 504G added to the set and shows a total size of 580. My original drive is an 80 that reports 78. The combination of the 2 as mfadd states gives me the 580.

Additionally after running the mfsadd, if I put the drive back into my tivo, it works fine - but if you go into the info screen it also reports 580.

Although Tivo is working, I am waiting for it to decide to write something somewhere within that last 80G. I'm expecting the unit will either display an error or more probably start crashing on me or freezing up or lying to me telling me it is recording things and then telling me at playback that they don't exist (I got this last one once)

Some more info

I have now tried this EVERY other way of performing this upgrade with the same EXACT results

I have now followed the instructions to do all of the scenareos applicable to single drive systems. EVERY time I am successful with no errors during any of the procedures and EVERY time I end up with the system reporting a drive more in space than it should be reporting.

I have done a disk copy using the dd command

I have done a backup / restore / expand using mfsbackup, mfsrestore and mfsadd. As well as the restore using the -x to expand instead of mfsadd

I have done the mfsbackup | mfsrestore

No matter how I go about copying the drive I end up with 504G added (the size of the entire drive) to the original 80G - leaving me with 580 hours.

NOTE: I realize that I did not type in exact commands in this note but I have to trust that I did not make any typos as I have gone through about 20 attempts with ALL of them completing each phase correctly/ without errors - and all bringing me to the same exact finishing point; 580G - the size of both drives together. If there is any question as to what command I typed - the answer is exactly what is written in the H manual as well as a few variations found through the forums and in the mfstools readme info

I have gotta think that if I am having this problem EVERYONE else trying to upgrade a single drive system is having the same exact problem. Doesn't anyone out there have any clue as to why this occurrs and how to properly upgrade the drive to the correct capacity.

OK - now I'm confused. You did a "dd" before you did the original mfsadd? The mfsadd command either adds two drives together, or adds the extra space on a drive as another partition set (or both). So doing mfsadd on only one drive as in your original post would serve to add extra unused space on a larger A drive - most likely the case if you've dd'd to another A drive that's larger.