The short answer is, NO.
The longer answer is, the burner in the Toshiba is probably capable of burning a Dual Layer disc. The problem is, the TiVo software doesn't know how to burn a Dual Layer disc.
Also, replacing the burner is a non-starter. I've been attempting to fix a broken Pioneer DVR-810H-S that has a bad burner. I thought I could simply replace the burner (a Pioneer DVR-A06-XA) with a similar Pioneer burner (a Pioneer DVR-106D). I can get it to play discs, but not burn discs. I think there is something special in the firmware of the burner that comes in the TiVos.
Hope this helps.