Download Final Fantasy - Kung Fu - Bug Fix ROM Hack

Final Fantasy - Kung Fu - Bug Fix - Version 0.8 (alpha)

Archive Contents

    README.txt                  This File
    kung-fu.sav                 SRAM save file for testing

    kung-fu-bug-fix.s           Fix Source Code
    kung-fu-bug-fix.o           Fix Binary Object

    kung-fu-bug-fix-nes.ips     Fix IPS Patch for ROMs with an iNES header
    kung-fu-bug-fix-raw.ips     Fix IPS Patch for raw ROMs

    kung-fu-bug-raw.ips         Bug IPS Patch for ROMs with an iNES header
    kung-fu-bug-raw.ips         Bug IPS Patch for raw ROMs

About

The reason for this patch is pretty simple. In Final Fantasy, the Monk type
classes (Black Belt and Master), have some special abilities. Firstly, when
they are unarmed, their Damage is equal to Twice their Level. This differs from
the other classes who's Damage is equal to half their Strength when unarmed.
Secondly, when they are unarmored, their Absorb (aka Defense) is equal to their
Level. Normal classes have an Absorb of zero when unarmored.

These special cases are implemented in the game code in two places. The first
is in the equipment subscreens. The second location is in the level up code.
The equipment code works the way it's supposed to. However, the level up code
does not.

The bug is pretty simple. When a Monk type character levels up, the code checks
if they are unarmed. If they are, it sets their Damage equal to their Level
times two and their Absorb to their Level. This has two effects. The first is
that characters who use a weapon, but no armor are denied their monk Absorb
bonus. The other effect is that characters who fight hand to hand, but wear
armor are given the bonus even when they shouldn't have it. Characters who wear
armor and use weapons, and those that do neither, are handled correctly.
(Although, it's pretty much a coincidence.)

There is an easy workaround for this bug, simply going to the armor subscreen
after your Monk(s) level up. You don't even have to do anything once you're
there, simply opening and closing the screen will correct their stats. However,
this shouldn't be necessary and can have negative effects on gameplay. For
instance, if you are unaware of the bug, it can negatively effect your
character's battle performance. Also, it can be exploited to gain special
effects from armor (such as the Ribbon), while still gaining the Absorb bonus.

The way the fix works is equally simple. It merely checks for equipped weapons
before applying the Damage bonus. After that, it checks for equipped armor
before applying the Absorb bonus. It's pretty basic.

Installation

To install the patch onto a Final Fantasy ROM image, use your favorite IPS
patching utility. As alway, it's recommended that you back up your image first
in case something goes horribly wrong.

The *.ips patch is for ROM images with a sixteen byte iNES header. The
*-raw.ips patch is for ROM images without a header. There is no patch for ROM
images in UNIF format at this time. (My apologies.)

For more information on other ways to apply the fix, see the Technical Details
section below.

Uninstallation

If, for whatever reason, you decide that to remove the patch, a set of reverse
patches has been provided for your convenience.

Testing

For ease of testing the effects of the bug and/or the fix, an SRAM save file
has been provided. It has been modified to make the bug easy to reproduce.

To perform the test, simply load the provided save game and select continue.
The party consists of four Monk type characters, each with a different
combination of armed and armored status. For ease of keeping track of who's
who, they all have special names, the meaning of which should be obvious.

Now, without changing their equipment, wander around until you hit a random
encounter. Beat the monsters (it should be a cake walk) and your entire party
will level up. This will trigger the bug in an unpatched version of Final
Fantasy.

After your party levels, go into the Status subscreen for each character and
note what their Damage and Absorb values are. (The bug only effects the middle
two characters and only effects Absorb, but this guide is for a thorough test.)

Then go into the Armor subscreen and out again. Go back to the Status subscreen
and you'll note that two of the characters have had their Absorb value change.
(If you want to be really thorough, go to the Weapon subscreen and then check
if Damage changed.)

Once the patch has been applied, there should be no changes to any of the
character's stats when performing this test. Be sure not to save the game
when testing, or the test case SRAM will be overwritten.

While this patch has been tested and found to work as described, it hasn't
undergone extensive testing. It is unknown if it works on the Japanese version
of Final Fantasy. It is also unknown if it works on real NES hardware as it's
only been tested via emulation. However, there is no reason it shouldn't.
(If you have a flash cart and are willing to test this patch on the bare metal,
please email me your results at "levi at gis dot net".)

For possible issues with compatibility with other FF hacks, see the Technical
Details section below.

Technical Details

The source code of the modified function is provided with this archive. It is
written in 6502 assembly and was written for and compiled with the p65
assembler. The code may require modification to work with other assemblers.

Also provided is the raw object file produced by the assembler. It can be used
with a hex editor to cut and paste the changes into a ROM image, if desired,
rather than using the provided patches.

The hack was created by disassembling the buggy code, writing a new version,
reassembling the results, and pasting them into a ROM image with a hex editor.

However, the resulting code was larger than the original, so additional space
needed to be found somewhere in the ROM. While looking for blank space in the
same bank (B) of the image (to avoid a messy bank switch), the first place
I found was at the end of the graphics used by the bridge crossing scene. The
last two tiles are blank and unused.

So the function was split into two parts. The first was placed where original
function was and the second was placed in the unused tiles of the BCS graphics.
Nothing else was moved or altered by the patch.

This means that the patch should be compatible with other hacks, as long as
they don't alter the modified level up code, or the bridge crossing scene. If
they do alter the graphics of that scene, then the patch may or may not work as
desired, depending on whether the last two tile where utilized or not.

If the space where the second piece of code was located is needed for another
hack, any sufficiently large space in bank B can be used to hold the code. This
will, of course, require modification of the first part of the code so that it
jumps to the correct location. The second piece of code should work fine
without modification.

Change Log

v 0.8    Initial public alpha release.

Credits

Final Fantasy is Copyright 1984 Square Enix.
This modification was made by Levi Aho on Friday October 26th, 2007.

The tools used where as follows:

    DCC6502 1.4                by  Tennessee Carmel-Veilleux
    Hexedit 0.9.7              by  Adam Rogoyski
        Romhack Edition        by  "Prez"
    P65-Ophis Assembler 0.7.2  by  Michael Martin
    gedit 2.18.1               by  The gedit Team
    Universal IPS              by  Neill Corlett
    FF Save Game Patcher       by  Levi "Karatorian" Aho
    Ispell 3.1.20              by  Pace Willisson & Geoff Kuenning

Special Thanx

    romhacking.net      Utilities, community, inspiration
    "Disch"             Save game hacking information, elite FF knowledge
    "Silver X"          Encouragement, documentation
    Y Dienyddiwr Da     FFBytes

Portions of this code are Copyright Square Enix and are used without
permission. All other contents Copyright 2007 Levi Aho.

This code may be freely used. This is not the GNU GPL. If anything breaks,
you get to keep the pieces. All documentation All Rights Reserved.

It is requested (although not required) that if you use this hack in a larger
project or similar compilation that I be notified, be sent a copy of the
released hack (patch only please), and be given credit for my contribution.
I can be reached at "levi at gis dot net".

Hack and enjoy!