This is an updated version of my original Newbie Guide to the HR10-250, updated to version 6.3 and with extraction instructions. I've posted the versions of the binary files that I use. These are not guaranteed to be the latest versions. See the appropriate threads for the latest versions of these binaries.
Here's a newbie guide to hacking the HR10-250 (HDTivo or HDT)
 Do I need to program the PROM to hack the HDT?
A. No. At one time you needed to, until the HDTeam figured out how to alter the boot so that software from the drive is run in a normal linux fashion. Now, it's all software.
 Do I need to take my HDT apart to hack it?
A. Yes, you need to do things to the hard drive (such as back it up).
 What do I get when I'm done?
A. With the current generation of stuff, you get ethernet access (via a USB ethernet adapter you buy), FTP access to the Tivo files, FTP access to the Tivo Videos, a Web-based Tivo control system, and the ability to save Tivo files to a networked PC hard drive (encrypted or unencrypted or in MPG format).
 How big are Tivo files?
A. For standard definition you can expect about 1-5GB/hour. For high definition it's about 5-10GB/hour. Size varies all over the place depending on how much compression DirectTV has applied to the video (how much bandwidth they allot the show).
 Can I use a Linux computer for editing drives rather than booting with the MFSTools CD.
Yes, I recommend that. Standard X86 based linux stores the partition table in a different byte order so you will need to run tivopart. The syntax is
tivopart.i686 r /dev/hdc
You can test that this ran correctly by trying to mount the drive data. Create a /mnt/tivo folder if you don't have one then
mount /dev/hdc4 /mnt/tivo
If you can view the files after it's mounted then everything is ready. Note that the files flipflop from hdc4 to hdc7 depending on version.