Phantasy Star 2: End game No Audio & Nei Sword Crash FIX

A short guide describing, and providing a fix to an unfortunate emulation bug that occurs right before the final dungeon in Phantasy Star 2.
Spoiler warning, obviously.

Bug Description:

Speaking to Lutz after colecting all 8 pieces of Nei Equipment in the Esper Mansion will cause the game's audio to cut out permanently, and using the Nei Sword will cause the game to crash.

Cause:

This bug is caused due to an imperfection within the emulator that the game is running on. There are also unconfirmed reports of this bug occurring on NA versions of the original carts, however aside from testimony, there is currently no evidence of this.

Fix:

This bug is thankfully easy to fix, simply follow the steps below.

STEP 1:
In the Esper Mansion, speak with Lutz for the first time to trigger the bug.
Finish the cutscene with Lutz, and there should be no audio at all.

STEP 2:
Repeatedly press the START button (spam it) until you hear the game's "pause" and "unpause" noise. Once you hear the noise, ensure the game is unpaused.

STEP 3:
Speak with Lutz again, and the game's music will return. You've now repaired your save of Phantasy Star 2. Not only does this restore the game's sound effects and music, but it also makes it so the Nei Sword works properly, and does not crash the game.

Conclusion

While it's fairly disappointing that SEGA officially sold this game alongside an emulator that cannot properly emulate it, I'm not entirely surprised. Hopefully this guide could help you out, and I hope you enjoy the ending of Phantasy Star 2. :)

[malasdair]

Excellent and useful note, but be aware the issue is not SEGA's emulation - rather, the issue is present in the original cartridge even on real hardware.