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Thread: Status: SamSho V Special Redump

  1. #51
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    Quote Originally Posted by Niko49 View Post
    Let me know if you need anything and I'll see if I or someone I know can help out!
    they could use a SSVS cart for testing I'm sure...

  2. #52
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    Quote Originally Posted by xsq View Post
    they could use a SSVS cart for testing I'm sure...
    So nice of you to volunteer yours! xsq, you're truly a legend.

    lol in all seriousness though, if they do need one. I'll probably start a group funding project to buy them one, or send them the cash to buy one.

  3. #53
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    Quote Originally Posted by Niko49 View Post
    So nice of you to volunteer yours! xsq, you're truly a legend.
    If only I had one, I'd wipe that smile of your face...


    Quote Originally Posted by Niko49 View Post
    in all seriousness though, if they do need one. I'll probably start a group funding project to buy them one, or send them the cash to buy one.
    I'm in then.

  4. #54
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    Any news on this matter? How would one make a "pop" free basara for the flashcart? Can I manually hexedit the V rom binary?
    Thanks to all involved !
    Neo Geo is just plain awesomeness.. gotta love it!

  5. #55
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    Quote Originally Posted by bytestorm View Post
    Any news on this matter? How would one make a "pop" free basara for the flashcart? Can I manually hexedit the V rom binary?
    Thanks to all involved !
    I'm curious as well what the status is.

  6. #56
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    I posted how to do that in the main NeoSD thread months back, its there somewhere.
    THE UNIVERSE BIOS ( MVS / AES, and now also for CD )
    www.universebios.com. Also on facebook, please like http://www.facebook.com/UniverseBios.

  7. #57
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    Quote Originally Posted by Razoola View Post
    I posted how to do that in the main NeoSD thread months back, its there somewhere.
    Cool, thanks!
    Neo Geo is just plain awesomeness.. gotta love it!

  8. #58
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    I think neodev is looking into correcting the PCM2 decryption. I'll reach out and see if thats still the plan.
    Last edited by Niko; 04-27-2017 at 08:25 AM.

  9. #59
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    Quote Originally Posted by Niko View Post
    I think neodev is looking into correcting the PCM2 decryption. I'll reach out and see if thats still the plan.
    Oh so it was indeed a decryption error and not a bad dump?
    Neo Geo is just plain awesomeness.. gotta love it!

  10. #60
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    Quote Originally Posted by bytestorm View Post
    Oh so it was indeed a decryption error and not a bad dump?
    Thats what it "appears" to be. However, Razoola mentioned there might be some special technique for reading the first 2 bytes of those ROMS. So thats still a possibility I suppose.

  11. #61
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    Quote Originally Posted by neodev View Post
    I missed these latest responses on this thread.
    Well, I'm probably getting a kof2002 cart, that I think uses the same pcm2 variation that ss5/ss5sp with the extra scrambling. Getting a SS5 or SS5SP is hard, as they are very expensive.

    What I plan is probing the address and data bus of the V1 rom (I only have a 16 bit logic analyzer, so I can only partially probe it) and then making the game (via a custom m1 rom or using another game CHA board) play that sample, and sniff the addresses and values it reads, and then probe the V1 address bus and the cart data bus, to check that the encrypted and decrypted values match with the ones currently in the dump and after decryption. If the encrypted value matches, but the decrypted one doesn't, then it's definitely something happening in the PCM2 that is different for offset 0. It might be that address 0 is swapped to a different address in the V1 rom space, but the address probing should show that (if that's the case, I'll move all the probes to the address bus and extract it in several tries).
    This might take a while, as I don't have the cart yet, and I need to find time to do that too

    Also about the HYCS circuit, it seems to keep the MSB address of the rom LOW as long as the included voltage supervisor signals the voltage is too low, or the IN_RST pin is low. I don't know what's exactly for, but I can only guess that it must be forcing that to 0 during startup because the PCM2 might be reading the decryption data from the V1 rom itself, and it's stored in a place with the MSB set to 0, and they have some kind of bug that makes the address MSB float (or input, as the bus is muxed with in and out signals) and they need to force it to 0. I will also sniff the V1 accesses during startup to check which addresses it reads before playing any sample (not easy, as the YM always generates addresses even if it's not playing data, it just generates the last address over and over, without increment)
    Hey @neodev, just wanted to see if you ever had a chance to dig further into this?

  12. #62
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    Thank you so much for this great job. Keeping the samurai shodown alive.

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