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Final Vendetta: AES & MVS Version available for Pre-Order

Flain said:
Hopefully the cart behaves when it finally comes out, my last purchase of a new neogeo game was Vengeance Hunters, which works great but when you put it in a multislot it never gives up its attract mode. So once the neogeo cycles through to vengeance hunters it stays there forever. Brought it up on their discord and looks like they no longer have the guy with the neogeo coding skills to fix it (the cart has a sdcard slot for updates and all too so could be fixed, but they lack the people/staff to do it).

Crossed fingers for this cart, but not overly hopeful
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I don't want to distract the discussion too far from Final Vendetta, but this is interesting. I just began to look at Knight's Chance in the MAME debugger because it does the exact same thing. It just loops its own attract mode and never moves on to another slot.

I know basically nothing about coding and assembly, so it is entirely possible that I don't stand any chance of figuring out how to make it work, but I've looked at how Metal Slug runs through its own attract mode in the debugger too and the process seems to make sense to me. I've found some locations where it is reading or writing the bit that controls the system rom status.

Relevant part from the dev wiki:
https://wiki.neogeodev.org/index.php?title=BIOS_RAM_locations#System_Related

$10FD81BIOS_SYSRET_STATUSbyteBIOSInternal value which stores the function code that SYSTEM_RETURN will call.
  • 0 : Init bram/select valid game for eye-catcher
  • 1 : Set the EL-LED to the correct value
  • 2 : Switch to the next slot, relaunch eye-catcher
  • 3 : After a gameover, save the playtime for bookeeping, switch to DEMO mode, reset the workbackup ram
  • 4 : Switch next slot (select p1 pressed)
  • 5 : Switch to previous slot (select p2 pressed)
  • 6 : Called after a coin deposit, does nothing
 
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lithy said:
I don't want to distract the discussion too far from Final Vendetta, but this is interesting. I just began to look at Knight's Chance in the MAME debugger because it does the exact same thing. It just loops its own attract mode and never moves on to another slot.

I know basically nothing about coding and assembly, so it is entirely possible that I don't stand any chance of figuring out how to make it work, but I've looked at how Metal Slug runs through its own attract mode in the debugger too and the process seems to make sense to me. I've found some locations where it is reading or writing the bit that controls the system rom status.

Relevant part from the dev wiki:
https://wiki.neogeodev.org/index.php?title=BIOS_RAM_locations#System_Related

$10FD81BIOS_SYSRET_STATUSbyteBIOSInternal value which stores the function code that SYSTEM_RETURN will call.
  • 0 : Init bram/select valid game for eye-catcher
  • 1 : Set the EL-LED to the correct value
  • 2 : Switch to the next slot, relaunch eye-catcher
  • 3 : After a gameover, save the playtime for bookeeping, switch to DEMO mode, reset the workbackup ram
  • 4 : Switch next slot (select p1 pressed)
  • 5 : Switch to previous slot (select p2 pressed)
  • 6 : Called after a coin deposit, does nothing
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We should maybe create another thread for this because it is an interesting topic! Was way too curious to not investigate this further (maybe for a reason :) ).

You are not wrong with the BIOS_SYSRET_STATUS value, although it does not seem to be the main cause of the issue with Metal Slug / Knights Chance.
What is happening with Metal Slug is that it calls the system_return BIOS function at the end of the attract mode, with a BIOS_SYSRET_STATUS set to 2 (this is set by the BIOS and not the game). The BIOS then checks for the next inserted slot, and if it finds one, it will change slot and ask the new game to start running the game from "DEMO" position (BIOS_USER_REQUEST = 2). If there is no more games inserted, it will just do the same thing but ignore the slot switching.

So what is up with knights chance? Well, if you set a breakpoint (you will find the address at 0xC00444) at the system_return function you would see that the game never calls this function, hence never returns the power to the BIOS to switch game. It loops in its own world and while it looks for the slot switching button, it does not honor the rolling slot switching feature.

Since knights chance is available for download, you could probably patch it by adding a jmp to system_return() at the end of the DEMO, but, it is a bit harder for games that only comes in cartridge form.
 
The latest news mentions a custom cartridge made by the Terraonion team to protect the data :) so no rom at all :)
 
ChrisBEANS said:
I have specifically asked BB about performance on multi slots on Twitter previously, and they seem pretty confident it’s been tested on all variants.
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Did you ask about the attract mode issue on other homebrew carts? "Tested" is a pretty lose term these days, maybe they plugged it in and the game booted up and said "yep tested"
 
Nic034 said:
The latest news mentions a custom cartridge made by the Terraonion team to protect the data :) so no rom at all :)
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Do you have a link to this news? I’m not seeing anything on the BB social medias and I haven’t received an preorder update email from them with this info.
 
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ShootTheCore said:
Do you have a link to this news? I’m not seeing anything on the BB social medias and I haven’t received an preorder update email from them with this info.
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I think he meant Vengeance Hunters, not Final Vendetta. This thread is getting confusing ?(

I don't think Bitmap have anything to do with Terraonion.
 
ShootTheCore said:
Do you have a link to this news? I’m not seeing anything on the BB social medias and I haven’t received an preorder update email from them with this info.
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Yep sorry, in mine mind, I was thinking « Vengeance Hunters »..8|:saint:
 
Edit: just to avoid confusion this post is about Vengeance Hunters not Final vendetta


fuzzbuddy said:
And they're still taking preorders knowing this bug is there?

https://shop.naluastudio.com/shop/products?show=vh_limited
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Flain said:
Oh wow i didn't know they were still trying to sell more carts, i thought that was done.

This was the response on discord when i asked for an update on my report that attract mode was broken:
"We have had issues with getting to the bottom of some issues that are specific to hardware interactions. The only people who could potentially assist are no longer working on such projects and we are doing the best we can. So I can't guarantee a fix, but I can at least say we're aware of issues and hope to resolve them."

I'll ask again.
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I said i'd ask again and i did, i was waiting incase i got an answer but it's been nearly 10 days now so here it is:

1754668313180.png


It's weird because i'm replying to a message, and he says "i'm not sure what you mean about the issue".. but it's discord.. so you click the message i quoted and it will take him to the message. So then i explain (again) and silence since the 1st of this month.

There has been no reply to my last message there, the channel in discord is sitting there at my last message as of today 9th aug 2025.
 
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LittleLarrySellers said:
I just got an email update from Bitmap... TLDR they apologize for delay and missing the latest Q2 date and are "very close" to getting this done!

No definitive date given but hopefully this means soon!

When will then be now? SOON!
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Weird that i didn't receive the update, the only email i have from them is the "order confirmed" email for a long time ago
 
I got the email and didn’t even preorder the game. You probably unsubscribed from their general mail list
 
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