This one acts just like the Yuffie warp bug but will take out all the way back to the Nibelheim flashback (the first town just as you leave Midgar). This is probably one of the best warps yet as it basically moves you back to almost the very start of the game.
To use this warp, have a save game right before the Nibelheim flashback. When fighting the dragon with Sephiroth, let the dragon kill you. Then wander around the area outside of Midgar and wait for a fight with a Devil Rider.
I've only experienced this twice; the first time and the second in which I duplicated it, so some of this procedure may not actually have any effect.
The way I triggered it is by encountering a single Devil Rider with a Kalm Fang. I killed the Kalm Fang, failed a steal on the Devil Rider with Cloud (the game said steal could not reach), then ran from battle. After running, an encounter with the Nibelheim flashback Dragon will occur but with your regular party instead of with Cloud and Sephiroth. You must DEFEAT the dragon which will then warp the game to the part where Cloud is telling everyone the story about Nibelheim at the Kalm Inn.
Whether killing the Kalm Fang or the failed steal is relevant, I don't know. But I was able to duplicate it with the procedure I outlined above.
I never did the Yuffie warp myself but I saw a video on it and this seems to be the same thing. I know some of you will be excited about this. Have fun with it.
