Toggle sidebar

What size are Gameboy opcodes?

Final Fantasy VII NES Demake (2026 Overhaul Updates)

DrgnMasterKota · 2026-07-12T08:48:15+00:00

This update project has been in the works solo development wise by me on and off for the last year with me completely reverse engineering and coding the game to implement many, many, many needed quality of life improvements to better get this NES Demake inline with the true source material of the original PS1 version. Currently this update goes all the way up to the Mr. Dolphin event in Junon with the Boss battle of Bottomswell. I just wanted to get a playable build out there in the wild for people to playtest and enjoy with the excitement for the updates to come which should be much faster now that I have decompiled all of the code base and understand what I'm working with. I also want to take this time to give full credit to the history work on this FF7 Demake. It started off as a NES Chinese game bootleg released by SHENZHEN NANJING. Then went on to become a massive 4 year long Rom Hacking passion project of Lugia2009 and his team of contributors Lindblum, Chpexo, FlamePurge, Dizzy9, Tsumai, Dr. Mario, Sirasu, keithisgood and Darkmew5. It's thanks to their hard work that we had the polished and happily praised V1.1 game update release that brought the original Chinese game bootleg up to standard. And now I'm doing the same myself as a solo dev to continue to improve the game beyond that standard with these 2026 updates. "This project sounds cool. But DrgnMaster what all does it really change and update?" I'm glad you asked, let me list a few examples. MAIN CHANGES FROM V1.1: - Adjusted the games encounter rate to feel more balanced and less overwhelming. (Yes no more getting into a battle every 3 steps) - Added new custom enemy encounter pools for specific story areas. (Each area now has it's respective enemies only, like the PS1 original, no more random enemies) - Improved enemy variety so different maps feel more distinct. - Increased battle run % chance from original 11% to a balanced 38% based on various level comparisons. - Preserved and improved key music/event cues while also restoring the 3 cut songs from the game "Trail of Blood", "JENOVA" and "Attack on Shinra". - Fixed various found text typos throughout the game. - Removed enemy encounter logic from any locations that shouldn't have it. That is just some of the many big improvements that I have been working on and done for the game. I'd love for this project to inspire other devs to want and contribute to this project further, potentially leading to more massive improvements or additions like adding Yuffie and Vincent into the game or even expanding the story out to fill in some of the missing jumped gaps from the original game. Download the latest update for the project here: How to Apply the Final Fantasy VII Demake V1.2 Patch This is an update patch for Lugia2009’s completed Final Fantasy VII Demake V1.1. What You Need: The original Chinese Final Fantasy VII NES ROM Lugia2009’s Final Fantasy VII Advent Children (Finished Version) Ver.1.1.ips Our Final Fantasy VII Demake V1.2.ips An IPS patching program such as Lunar IPS or Floating IPS Installation: Starting from the original Chinese ROM: Make a backup of your original ROM. Apply Lugia2009’s V1.1 IPS patch to the original Chinese ROM. Apply Final Fantasy VII Demake V1.2.ips to the newly patched V1.1 ROM. Launch the finished ROM in a compatible NES emulator. Already have Lugia2009’s V1.1 ROM: Apply Final Fantasy VII Demake V1.2.ips directly to it. Required V1.1 Base ROM The V1.2 patch must be applied to this exact V1.1 ROM: SHA-256: 240b14662c4cd53a5dc1abf6ee4ec4d5fb1d90b5a2109e50c5e20d30b87eaffb Correct Final V1.2 ROM After patching, the completed ROM should have: SHA-256:108ebeb2fb16e30d1b70ba7ec0d0e9106e0ff6f1cc0cd33c22872f8a51fb7113 Important Do not apply the V1.2 patch directly to the original Chinese ROM. Lugia2009’s V1.1 patch must be applied first. If the game does not work correctly after patching, verify that you used the correct V1.1 base ROM and applied the patches in the correct order: Original Chinese ROM → Lugia2009 V1.1 IPS → Final Fantasy VII Demake V1.2 IPS Link to Lugia2009's V1.1 update patch: https://www.romhacking.net/hacks/1657/ For ease of use feel free to use this online IPS patch website: https://www.marcrobledo.com/RomPatcher.js/ Also make sure to use the NESTOPIA emulator via Retroarch or Standalone as it's the only emulator that supports all the games tweaks and twerks done by everyone over the years. I hope everyone enjoys the update and please feel free to comment below your thoughts on any other potential improvements you'd like to see make it's way to the game. For any questions or if you are interested on helping with the project feel free to add me on Discord @DrgnMasterKota

Thread starter StackMasher
Start date Apr 11, 2017
Views 5,995
Replies 2

StackMasher

Well-Known Member

Member

Level 3

Apr 11, 2017

All I could find is this: http://www.pastraiser.com/cpu/gameboy/gameboy_opcodes.html
Presumably they are 1 byte, with an optional 1 byte prefix? Just making sure

daxtsu

Well-Known Member

Member

Level 15

Apr 11, 2017

1-3 bytes, it depends (I'm including immediate data in that assertion, and it looks like that table does too, meaning that the opcode is always one byte*, but it can include up to two bytes of data after). The table shows you how many bytes are in an opcode (the number on the left in the 2nd row of each entry):

*CB opcodes (as in an opcode that uses the CB prefix) are always two bytes.

Last edited by daxtsu, Apr 11, 2017

FAST6191

Techromancer

Editorial Team

Level 33

Apr 11, 2017

Better guide for an overview
http://bgb.bircd.org/pandocs.htm#cpuinstructionset
though as a quick reference once you know I do prefer the style you linked for which you can have another version of that http://imrannazar.com/Gameboy-Z80-Opcode-Map