Region free BIOS for MEGA-CD Version 2.00

Discussion in 'Sega Discussion' started by l_oliveira, Oct 25, 2014.

  1. TennokoeJames

    TennokoeJames Active Member

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    It does yes. no freezing.
     
  2. TennokoeJames

    TennokoeJames Active Member

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    Maybe just try patching it anyway?
    I know you say it's identical, but the universe doesn't always make sense ;)
    If it doesn't work, we'll know it's the patch that's breaking it for real hardware.
     
  3. l_oliveira

    l_oliveira Officer at Arms

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    Most curious, the file I have works on Kega Fusion and on MEGA-CD2...
     
  4. TennokoeJames

    TennokoeJames Active Member

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    Yeah it's weird. :confused:
    But as I say, the bios image that was dumped by my Everdrive works fine.
    Splash screen appears, menu works, JPN games work.
     
  5. TennokoeJames

    TennokoeJames Active Member

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    Also odd that the patched CD2 bios' that aren't even made for the M2 should work OK apart from the weird static issue.
    Maybe there was some subtle hardware or bios revision that didn't warrant a new number.
     
  6. TennokoeJames

    TennokoeJames Active Member

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    Do you have any ideas, or should I just make do with the CD2 bios and the static noise?
     
  7. l_oliveira

    l_oliveira Officer at Arms

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    CD2 BIOS handle audio muting differently like I said the control register takes an inverted value.

    Sadly the Wondermega 2/X'EYE BIOS only works on a Wondermega 2/X'EYE so I can't properly test changes made to it without one. The very same hardware differences don't block the CD2 BIOS from working with the WM2/X'EYE but affect how the CD2 BIOS behaves.

    I was given a faulty Pioneer LaserActive unit and a leaking caps SEGA PAC S-10 which after I repaired both I was able to put out patched versions of the four variations of the LaserActive SEGA BIOS for it. I had to spin several versions until I had a proper grasp of what was going on with it.

    So, until I figure out what's going on, I suggest you use original unpatched X'EYE and WM2 BIOSes with your unit for USA and JPN discs. If I ever get this to work correctly you will be able to use PAL discs with it, too.
     
  8. TennokoeJames

    TennokoeJames Active Member

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    Can you use me for testing?
    I have games of all regions and it would be quick to check each one.
    Or would you not be able to make blind changes to it?

    The process could be sped up even more if you have WhatsApp on your phone, so I can instantly know when you need one testing.

    Up to you though, bud :)
     
    Last edited: Aug 28, 2017
  9. l_oliveira

    l_oliveira Officer at Arms

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    Have this one a go. It's the same one as before but it has CRC checks disabled. If the problem is the CRC then this one should run.

    If the problem is the CRC I'll investigate a proper fix.
     

    Attached Files:

  10. TennokoeJames

    TennokoeJames Active Member

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    Sorry for the delay. I was asleep :p
    Just tested it and it behaves the same:
    Sometimes a black screen, sometimes freezing on the Wondermega splash screen before anything moves.
     
  11. TennokoeJames

    TennokoeJames Active Member

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    Me again! :p

    Do you have any other ideas?
    Or am I gonna have to buy you an X'eye? Lol
     
  12. l_oliveira

    l_oliveira Officer at Arms

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    Most curious is that the hacked WM2 BIOS I posted works perfectly (save for the CD DA muting problem we mentioned) on a SEGA-CD2 unit.
     
  13. TennokoeJames

    TennokoeJames Active Member

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    That is pretty curious.
     
  14. l_oliveira

    l_oliveira Officer at Arms

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    Very. I just mean to tell that I tested it with the hardware I happen to have here. And it doesn't work with emulators due to the hardware the emulators actually emulate.

    The CD-ROM drive used on the Mega-CD has two "processors" one is called "CDD" (CD Decoder) and the other is called "CDC" (CD Controller). The CDD is a SANYO chip which issoftware compatible on all units (LC8951/LC89513/LC89515) and does not present a problem.

    But different drive manufacturers have different CPUs controlling their drive (CDC) and the slight differences on chip behavior due to subtle firmware programming differences cause some BIOSes to not work on certain hardware.

    For example KEGA Fusion emulator emulates a SEGA/MEGA-CD1 with a SONY tray type drive (which happens to be the most common kind of SEGA/MEGA-CD1, mind you) and the X'EYE/WM2 BIOS doesn't work with it due to CDC behavior on the SONY drive being different. It boots, shows logo, plays music, reads discs but crashes once you try to start a game at the dashboard menu.

    A LaserActive can run any SEGA/MEGA-CD BIOS but it's BIOS only works on the LaserActive due to the extra MEGA-LD drive hardware.

    I am not asking you to buy me a X'Eye, that for sure lol.
     
  15. TennokoeJames

    TennokoeJames Active Member

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    Pretty weird that the WM2 would run the CD2 bios with only that odd burst of static to spoil things o_O

    I meant what I said though, dude.
    If you can't do this without the actual hardware in front of you, and you are willing to sink your time into it, I am perfectly willing to front some cash for a console (a cheap one. No mint condition museum pieces. Lol).
    After all, I am in a definite minority of people that actually use their WM2 instead of sticking it on a shelf.
    The fact that the problem with the previously released bios didn't get mentioned for ages demonstrates that. Lol
     
  16. l_oliveira

    l_oliveira Officer at Arms

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    The LaserActive and S-10 modules I took in were faulty and I needed to service them. The S-10 pac was mostly working but it had leaky caps. The LA main unit was very faulty and needed major rework.

    So I'm fine with taking in a faulty unit for repair, and then try making this work, of course.
     
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  17. TennokoeJames

    TennokoeJames Active Member

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    Cool beans. :)

    I only have my minty one.
    But again, perfectly happy to pay for a broken one, if you can find one locally (I'm in the UK)
     
  18. TennokoeJames

    TennokoeJames Active Member

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    Another interesting thing:
    Apparently the X'eye bios doesn't work on the WM2 either.
    Just tried stock X'eye bios files from several locations and they all freeze on the splash screen.
     
  19. l_oliveira

    l_oliveira Officer at Arms

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    I never did X'Eye because I never found a working copy of it's BIOS. lol
     
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  20. TennokoeJames

    TennokoeJames Active Member

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    Ah right. Haha.
    That'll be why they didn't work then :p
     

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