Cross-post from Board 2
Ever wanted to make the stages in Mega Man 2 revisitable? Well, now I just realized by changing one little byte will make revisitable stages in Mega Man 2 a reality. Don't believe me? Well, do as Bruno Mars says and just watch! (bad pun is bad :p)
First off, you'll need a Mega Man 2 rom. Don't ask where to get it, I'm not telling you. You'll also need a hex editor and an NES emulator. You have all that? Good! Now, in your hex editor of choice, in your Mega Man 2 rom, go to address 0x0340ec. You should see a byte "A5". Got it? Good. Now, change that byte from "A5" to "A6". Save your work. Run an emulator and beat a stage or 2 (Or enter A5 B2 D5 D4 C5 C1 B4 D3 E2 in the password screen to have all but Quick Man defeated) and then reselect the stage you beat.
Yes. It is possible! And the best part? You keep the weapons you gained! Don't believe me?
The Crash Bomb, in Crash Man's stage!
The Metal Blade... in Metal Man's stage!
The Leaf Shield...in Leaf, er uh, I mean, Wood Man's stage!
Special thanks to this link on Data Crystal
for helping me realize this.
Edit: As stated by Zieldak (from Board 2):
Yes, they are still there, and the weapon get still appears.
However, I have some problems with this find. It's not necessary working as it is believed to be.
'A6'-ing it simply doesn't work, it doesn't let the player to revisit all levels sometimes. Try this for better results. Of course, this is still not the best way to do this. Especially if you don't want the intro, get weapon and the bosses reappear.
So as of now, there are 2 ways: the original way and the improved way. The improved way makes sure you can revisit all the stages. It does display the boss intro and Get Equipped with screen.