These are the procedures that I took to replace a failed primary drive in my TiVo. Keep in mind that 6 months ago I upgraded my TiVo with a larger secondary drive. This allowed me the chance to backup my primary drive. I will document the procedures to making that first upgrade and backup at a later date. All software with the exception of the back image are contained on the MFSTOOLS CD. This is a downloadable .iso image that can be burned to a CD. This procedure is not a complete instructional but merely the steps I took in this one task.