This patch identifies the mistaken attribute on Steiner's Thunder Slash that made it a useless ability. It now works correctly, with good utility for its availability in the game (end of Disc 3) before you can make use of Shock; in fact, it can still be a useful ability in Disc 4 if you're already hitting the 9999 damage cap with Shock and want a more MP-efficient alternative.

The patch author states "This will not work on Beetle PSX for whatever reason (goes to a black screen in battle), but every other emulator is confirmed to work." This is because Beetle PSX is an accurate emulator that requires matching EDC/ECC data on the ROM; the game will get stuck on a black screen because it is attempting to regenerate the original data from the ECC checksum due to a mismatch. To make this patch work on Beetle PSX or Mednafen, you can use error_recalc.exe or EDCRE on the patched ROM.