You can find tutorials on websites such as RomHacking or RomHackPlaza.
Depending on the console of the game you are trying to hack, things might be a bit different.
Using hex editors is especially useful for older consoles that didn't support any standard filesystem... (including GBA)
For those games, here's the usual method:
Corrupting the data:
This is an important method for discovering the meaning and effect of each portion of data within the ROM.
1-
Corrupt the ROM: Replace a portion of the data with Zero Characters (aka Null Characters) or randomly generated data.
2-
Test the Game: Play the game and observe changes.
These could include graphic corruption, level design corruption, text corruption, music glitches, stat changes, or outright crashes (usually indicating programming code).
3-
Document Changes: Record any observed changes or lack thereof. Specify the address range and provide a description.
Example:
Code:
00003000-00003500 Overworld Sprites
00003A00-00003F00 Text
00003F00-00004400 Crash at Stage 2
00004400-00004900 No change
Afterward, undo the changes and proceed to corrupt the next portion of the ROM.
4-
Create a General Map: Continue this process until you create a general map of the ROM's data.
5-
Refine Your Focus: Identify the parts of the data you want to hack. Corrupt smaller portions of those areas until you pinpoint the exact range of each data you're targeting, then document it.
Example:
Code:
000024EA-000024EC Stage 5 MusicID
Some ROM maps for certain games have already been documented and can be found on ROM hacking websites.
Challenges ROM Hackers Face
We have covered just the basics so far.
Rom hackers usually face many obstacles depending on the game.
Encoded Text:
Older consoles sometimes use non-standard text encoding, making text unreadable. This text can often be remapped to normal characters.
Example:
Code:
Text:
08 05 0C 0C 0F
08 = H
05 = E
0C = L
0F = O
Remapped Text:
HELLO
Using the
Relative Search feature in hex editors can help identify encoded text efficiently.
Compressed Data:
Many games use custom compression algorithms for text, graphics, music, etc.
Reverse-engineering the algorithm typically requires programming skills to create unpacking/repacking tools specific to the game.
Some companies reuse algorithms across multiple games, and ready-made tools may already exist.
Always research the game and its developer to gather pre-existing tools and resources.
Modifying Programming Code:
Each console has its own assembly language.
To modify a game's logic, you need decompiler tools specific to the console.
Usually you need to document the address range of the code beforehand.
Hacking Music:
Depending on the console and developer, there may be tools available for creating custom game music.
Each of these sections, requires specialized tutorials.
Hacking some games is rather easy, while others could make even super experts cry.
I hope this helps.
