I always like to see posts that wrap up a problem (with lots of details) so I'll post mine.........
Platform: Dell XPS Gen 3 running XP SP2
DVD burner: Philips DVD8631 FW BD10 November 2004
DVD STB: Samsung DVD-S221
Disks: TYG02 Taiyo Yuden -R
Problem: Burned -R disc won't play on the S221 (in fact I took the disk to BB and CC and it wouldn't play in a brand new Samsung or a JVC or a Marantz...they should all play -Rs). I tried upgrading the FW from Dell to CD21...no luck). +R's work fine.
Solution: Used WinDWFlash to flash to G7L9 (you may be able to skip this step), then used the same WinDWFlash to flash to B7P9. Now the drive is a BenQ DVD DD DW1620 and it burns disks that my Sammy can read!
Got the flash tool and the .cvt's from the unofficial BenQ website (you need WinRAR to extract the .cvt).
Be careful of those that post and say, "Mine works great!". They probably haven't tried the disk on multiple players only one or maybe two. The combination of media/burner/player is important. I tried my disk (that was burned with the Philips FW) on at least five computers and about eleven set top boxes to find out that it did not work on some combinations.
With that said I am making one final assumption.....the successful disk I just burned that will play on my Sammy has not been tested on all those other machines. I will do that. If it doesn't work I will post here. But for now I think it will work.