tekken patch on NEO2?
 

This is just an observation. I tried to back-up my copy of Tekken Tag and my copy didn't work. I then applied the tekken patch to the disc image, and using the same process and the same type of disc i burned it again and it did work. I've got a Neo2 chip, and i know you shouldn't have to patch, but...

make a copy of TTT using Nero.

To play the game:

Insert your AR2/GS2 cd in the console and put it on stand-by (red-led).

Press the reset-button 'till you see the screen of Sony Computer etc.
Release the reset-button (tray will open and close)
select Start Game, Without codes.
replace your AR2/GS2 cd with the backup
wait 'till the cd spins up
press x