One of the seminal programs in Tivo and DVR history, mfs_ftp.tcl, has gotten a little long in the tooth. Complexities in updating/patching because much of its power comes from previous work and there are some sensitivities from both the pioneers and the author.
90%+ of Tivo and DTivo users have probably moved on and don't care
But for those who might care, a recent attempt to take a new look at the functionality is a program called tyftpd.tcl, a very nice piece of work that is worth a look if you'd like to have that functionality.
Attempts are being made to smooth its interface with another program called MovieLoader. A successful result here would be a huge step forward for those of us who are using older Tivos, for examples the HR10-250 or older DTivos or SA Tivos.
I can't point you specifically to where this is being discussed, but a search on tyftpd.tcl might be productive