i install a messiah in a ps2 with a gh015 bios i supposed it's a v5 although i never encounter a v5 with gap bios and boots originals, ps1 orig and backups, but no ps2 backups nor cdr nor dvdr.
i use the diagrams for v5/v6 and config the messiah for a v5, soldering the 4 points in the chip
when booting backups of ps2 it display's the red screen asking to use a ps1/ps2 disk.
i try using ar2 and it works with ps2 cdr's. don't know how to use it to play dvd'r also.
it's possible that the chip won't work with this ps2 or did i miss something.