So thanks to this forum I got the general game plan on how to upgrade my Bolt drive from 500GB to 3TB. The one thing there seems to be in the forums are big debates on whether to go internal or external drive as well as if a drive will "work". My setup worked great and was easy. For those looking to do an upgrade here is what I did. I bought a WD 3TB Purple drive ( https://amzn.to/2UcA2wS ) which is a 3.5" drive so I used a Rosewell enclosure ( https://amzn.to/36I6Alf ) and then a SATA cable from the internal tivo port ( https://amzn.to/2uRJ6g6 ) connected into a SATA extension cable ( https://amzn.to/2RK6vsQ) that plugged into the WD 3TB drive inside the Rosewell enclosure. I used the Rosewell enclosure for power to the drive and cooling. For now, I did not cut the Rosewell rear of the case or the tivo case. My system is in a closet so I left the rear of the Rosewell case off to let the SATA cable run right out the back. For the tivo, the covers are off completely and SATA cable runs right from the tivo to the extension cable which goes into Rosewell. Once I get everything settled in I may make cutouts in both cases for the SATA cable or just decide to leave them off since nobody sees the units. The WD 3TB is a "PMR" drive designed for constant writing. I have 4 tuners and it has no problem keeping up with all 4 plus reading to playback recordings or live tv. RPM's when I check typically 1000 to 2000 which is well under the 5400rpm maximum for this drive. Thanks to the forum here I learned about PMR drive types for AV use. Good info. So on my Bolt, this combination worked great, was simple to do and was plug and play since it was a 3TB capacity drive. I just had to do the guided setup again and redo my settings afterward. Keep in mind you will lose all your recorded shows on your old drive since it is no longer connected. I left the original 2.5" drive in the tivo case but it isn't plugged in as the new drive uses its SATA port. This way if my 3TB drive ever does go I can just plug the internal back in and pair the cable card again and I'm back in business, albeit with just 500GB! On an unrelated note: BEFORE I installed this drive I had issues with the Tivo guide for a few select channels where it wasn't loading the right shows and the descriptions were generic (i.e. didn't show guests for a talk show). The 2nd bolt I bought at the same time had the correct guide data. Talked to tivo support they had no idea why this happened so they are sending me a new Tivo replacement so I'll have to do the drive upgrade again in the new one. I figured since the tivo was already buggy with the guide data in its unaltered out of the box state it was a good time to test this replacement drive and I hoped running guided setup again and a brand new clean drive would fix it but it made no difference. It's a very bizarre issue. Not sure if anyone else has ever had it here. So first thing I'll do when I get the replacement Tivo unit is install this new drive so I only have to do guided setup one time.