Under the microscope: Legend of Oasis (Saturn)

a.k.a. The Story of Thor 2

Back in 2024, I posted this about Legend of Oasis (a.k.a. The Story of Thor 2), the 1996 action RPG for Saturn:

THE LEGEND OF OASIS has a debug mode that’s been known for ages - lots of sites have an Action Replay code for it.

I found how to unlock it with a button code! Hold Right+Z+Start when beginning the game. When you do it this way, you also get a ton of items and maxed stats.

I couldn’t find the original source for the Action Replay code - the earliest reference I could find on the Wayback Machine is from 2017. But I’m reasonably sure that it was known before the 2010s.

The Action Replay code works by modifying the value at 06088724:

From GameHacking.org. The code is attributed to users Code Master and ripi3top

After entering it, a banner during gameplay indicates that you’re in DEBUG MODE, and special debug controls are activated.

The cheat method described above - holding Right+Z+Start when beginning the game - does that, plus more: it maxes out your stats:

Debug mode with max stats

This is Ghidra’s decompilation of the function at 06009cc4, which checks for the button combination:

  if (p1_held_06096a4a == 0x188) {
    debug_gate_01_06088724 = 1;
    timer_060886a0 = 0x1464b3f;  // 99 hours
    spirits_0608870e = 0x3f;    // All six spirits
    held_weapon_0608870f = 0;
    bombs_06088710 = 99;
    keys_06088711 = 99;

0x188 is the logical OR of Z (0x100), Start (0x80) and Right (0x8). You can see that after the button check, the debug address gets set and that various stats get maxed out. The Action Replay code bypasses this function, which is why it doesn’t max your stats.

Here’s something I missed when I looked at this game back in 2024: There’s actually another way to activate debug mode without hacking. The function at 002e8a38 executes when you’re on the mode select screen.

The mode select screen

This function checks:

• Whether the New Game is being highlighted.

• Whether Controller 2 is holding down R.

• Controller 2’s progress toward entering this button sequence: Z, A, Up, Y, Right, Right, L.

If you put that sequence in correctly, the debug address from above gets updated. No stats get maxed out, though - it’s like using the Action Replay code.

Debug mode enabled, no stats have been boosted

This version of the debug code allows you to do something else, however. If you hold L+R+Left+Z and press C when starting a new game, the ending FMV plays and then the staff credits roll.

The ending credits

You don’t get to put in your initials after the credits if you cheat - the function at 002e55a4 handles name entry, and it bails out early if it sees that the debug address is set.

The name entry screen

---

Outro

Thanks for reading. I’ll be back with more articles on retro game reverse engineering soon. Subscribe to the e-mail version of Rings of Saturn to get the next edition as soon as it’s published.