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When I was a kid, I played Heavyweight Champ and found this cheat we could never reproduce. We called the Sega Hotline here in Australia and they had no idea (thanks $4.95 a minute).

So here's what I know. It was Heavyweight Champ, not the rebranded Buster Douglas or George Foreman games. It was in Australia so it was on a PAL game/machine.

In the intermission you could mash the controller and get a message that said something like PUNCH or RECOVER.

Now, I think I've found it in the ROM. Starting at 00002140-0F we have

PUNCH:^1:*Á(€2*Ák!!|ÑRECOVER:^40:

So here's where I'm stuck... I know you can trigger it in the intermission, but I don't know if I'd need to dissamble the code to find out more. I think it would be cool to find a cheat code that has never been found.

What do you think?

Awesome.
In a similar fashion I found a cheat to tranform in Wonderboy III SMS in the first town, by walking right, jumping and pressing fire at the highest point many many times.I was able to transform into wonderboys actual human boy form. Never was able to repruduce it, not that I tried. Not 100% sure about the details. Perhaps It was at the other side of that wall (so walking left) and being much further on in the game. But it was that wall.

I've discovered an undocumented cheat but it doesn't seem to be linked to what you described. Here is the cheat I found:

At the speed select screen, on controller 2, press U, D, L, R, U, D. A 'T' will appear in the top-right corner to indicate the cheat has worked. During gameplay, pause the game and press Up for 9 power punches, Down for full health, Button 1 to win the round and Button 2 to win the fight. Pressing those buttons on controller 2 will do the same for player 2.

Emulicious' disassembly found it quite easily, but it's behind a whole load of conditions that I couldn't identify. It doesn't seem to be a simple keypress sequence.

Maxim wrote

Emulicious' disassembly found it quite easily, but it's behind a whole load of conditions that I couldn't identify. It doesn't seem to be a simple keypress sequence.

Thanks for looking into it Maxim. I downloaded Emulicious and the assembly was a bit over my head. It's nice to know it is there buried in the code and it can be triggered somehow!

Ian, that's really cool to find another cheat. That one would have been amazing to know back when I had my SMS set up as a kid. This game is pretty brutal in the difficulty level.

So I think I've worked out how to trigger the intermission bonuses.
As Maxim mentioned, there's several conditions:

Then during the intermission, press button 1 x 20. This doesn't work every time though. Which bonus you receive is pretty much random. You can only do it 3 times.

Thank you Ian!!!!

You solved a childhood mystery that I've been wondering about for 30+ years. It feels good to know it exists. And that it required a fairly specific set of circumstances.

You're an absolute champion. Thank you so much.

heavyweight champ mystery solved.jpg (166.68 KB)

No problem, thanks for bringing it our attention.

This also works for George Foreman KO Boxing, but you only have to press button 1 x 10.

Author	Message
initials Joined: 10 Oct 2022 Posts: 5	Heavyweight Champ Undocumented Cheat Posted: Mon Oct 10, 2022 12:51 pm
initials Joined: 10 Oct 2022 Posts: 5	When I was a kid, I played Heavyweight Champ and found this cheat we could never reproduce. We called the Sega Hotline here in Australia and they had no idea (thanks $4.95 a minute). So here's what I know. It was Heavyweight Champ, not the rebranded Buster Douglas or George Foreman games. It was in Australia so it was on a PAL game/machine. In the intermission you could mash the controller and get a message that said something like PUNCH or RECOVER. Now, I think I've found it in the ROM. Starting at 00002140-0F we have PUNCH:^1:Á(€2Ák!!\|ÑRECOVER:^40: So here's where I'm stuck... I know you can trigger it in the intermission, but I don't know if I'd need to dissamble the code to find out more. I think it would be cool to find a cheat code that has never been found. What do you think?

D Joined: 01 Apr 2005 Posts: 250 Location: Almere, The Netherlands	Posted: Mon Oct 10, 2022 2:02 pm
	Awesome. In a similar fashion I found a cheat to tranform in Wonderboy III SMS in the first town, by walking right, jumping and pressing fire at the highest point many many times.I was able to transform into wonderboys actual human boy form. Never was able to repruduce it, not that I tried. Not 100% sure about the details. Perhaps It was at the other side of that wall (so walking left) and being much further on in the game. But it was that wall.

ian Joined: 01 Mar 2006 Posts: 85 Location: Essex, UK	Posted: Mon Oct 10, 2022 5:10 pm
ian Joined: 01 Mar 2006 Posts: 85 Location: Essex, UK	I've discovered an undocumented cheat but it doesn't seem to be linked to what you described. Here is the cheat I found: At the speed select screen, on controller 2, press U, D, L, R, U, D. A 'T' will appear in the top-right corner to indicate the cheat has worked. During gameplay, pause the game and press Up for 9 power punches, Down for full health, Button 1 to win the round and Button 2 to win the fight. Pressing those buttons on controller 2 will do the same for player 2.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14740 Location: London	Posted: Mon Oct 10, 2022 7:08 pm
	Emulicious' disassembly found it quite easily, but it's behind a whole load of conditions that I couldn't identify. It doesn't seem to be a simple keypress sequence.

initials Joined: 10 Oct 2022 Posts: 5	Posted: Mon Oct 10, 2022 10:24 pm
initials Joined: 10 Oct 2022 Posts: 5	Maxim wrote Emulicious' disassembly found it quite easily, but it's behind a whole load of conditions that I couldn't identify. It doesn't seem to be a simple keypress sequence. Thanks for looking into it Maxim. I downloaded Emulicious and the assembly was a bit over my head. It's nice to know it is there buried in the code and it can be triggered somehow! Ian, that's really cool to find another cheat. That one would have been amazing to know back when I had my SMS set up as a kid. This game is pretty brutal in the difficulty level.

ian Joined: 01 Mar 2006 Posts: 85 Location: Essex, UK	Posted: Tue Oct 11, 2022 1:27 am
ian Joined: 01 Mar 2006 Posts: 85 Location: Essex, UK	So I think I've worked out how to trigger the intermission bonuses. As Maxim mentioned, there's several conditions: - It has to be at least Round 3 - You have to have less than 48HP (about a quarter of a bar) - You have to have less than 2 Super Punches Then during the intermission, press button 1 x 20. This doesn't work every time though. Which bonus you receive is pretty much random. You can only do it 3 times.

initials Joined: 10 Oct 2022 Posts: 5	Posted: Tue Oct 11, 2022 2:11 am
initials Joined: 10 Oct 2022 Posts: 5	Thank you Ian!!!! You solved a childhood mystery that I've been wondering about for 30+ years. It feels good to know it exists. And that it required a fairly specific set of circumstances. You're an absolute champion. Thank you so much. heavyweight champ mystery solved.jpg (166.68 KB)

ian Joined: 01 Mar 2006 Posts: 85 Location: Essex, UK	Posted: Tue Oct 11, 2022 1:17 pm
ian Joined: 01 Mar 2006 Posts: 85 Location: Essex, UK	No problem, thanks for bringing it our attention. This also works for George Foreman KO Boxing, but you only have to press button 1 x 10.

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