The stock 500GB Seagate Pipeline HD drive found in the THR22-100 is probably running custom firmware; when connected to a PC, it give errors or hangs the bios depending on the motherboard. This probably isn't due to SATA locking as unlocking sofware reports the drive as unlocked with unknown problems; copying the original drive does not appear possible at all. Meanwhile, the THR22 behaves like DirecTV DVRs in that it will format a blank internal drive and then start using it. And the resulting disk has a partition layout that the mfslayout.sh script on the JMFS iso can read. So what is probably is possible is to install a blank consumer drive and then later either make an image copy to a new drive of the same size or using the JMFS iso to copy/expand to a larger drive. Of course JMFS has a size limitation of 2TB so it might be best to just start with a 2TB drive. That way a simple image copy could be used to replace a failing drive or even make periodic backups.