Ty1to2
From DVRpedia
Overview
Shows extracted with a Series 1 TiVo are not compatible with the format used in a Series 2 TiVo, so the Series 1 shows can't be re-inserted into the Series 2. The problems is that there is no audio after the reinsertion into the Series 2. A program named Ty1to2 was created by DealDatabase.com user bcc to correct this problem by converting a Series 1 file to the Series 2 format.
Details
The latest version of the converter is version 1.5. Download the files attached to this Dealdatabase.com post, unzip them, and follow the instructions.
Discussion and support for this file is available in this DealDatabase.com thread: http://www.dealdatabase.com/forum/showthread.php?t=32022&page=5&postcount=5
Converting to TMF files
The Ty1to2 program is not compatible with TMF files. TMF files must be converted to TY+ files using details in this DealDatabase.com thread: http://www.dealdatabase.com/forum/showthread.php?t=44588