Tutorial to Unlock Biollante (You're sacrificing Mecha Ghidorah for this. Please be aware of this. Also I'm NOT responsible if you end up wrecking your game/computer.) If another monster has the same amount of letters as Biollante, go ahead and try it.
Stuff you'll need:
1. Winrar. This is needed to extract ISO files.
2. Godzilla STE ISO. You'll need it so you can mod it.
3. PSPad Pspad.com
1. Extract the contents of the ISO into a folder using Winrar.
2. Open GODZILLA.vol with the PSPad hex editor
3. This is a big file. It can easily crash the hex editor. Press CTRL + H
4. In the "Find" box, type mghidorah
5. In the replace box, type biollante(I also clicked ignore character case. Probably not needed)
6. Click Replace
7. It'll take a while. Give it some time. Once they are all replaced, save the file.
How to play it:
There are two ways to play it, emulator or PS2
1. PCSX2 (The PS2 emulator)
2. Configure it and get the bios(I'm not telling you to go download them as its illegal to download them)
3. IMGBurn (you should have already downloaded it)
1. Open IMGBurn
2. Find the folder with GODZILLA.vol and all the other files
3. Let it compile it into an ISO(Click "Ok" for everything that pops up)
4. Open the ISO with PCSX2
5. If all went well, go to Mecha Ghidorah(His name and small icon will still be there but when he is played as, it should be Biollante)
6. Press whatever button you configured as "X" and have fun!
The only way to play it on the actual PS2 would be to mod your PS2 and burn the disc. I will not go into detail about this.
Feel free to ask questions!
On September 15th 2013, Biollante's files were recovered and hex edited back in. This discovery quickly became popular, and I got 180+ subscriptions on Youtube because of this. About a day or 2 later, a tutorial was posted on the Gigan vs Biollante video explaining how to unlock her.
May 27th, 2014, the tutorial is now on Moddb.
Thanks for everything guys! :D