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Ati X550 Pci-e Bios edit

Discussion in 'AMD / ATI' started by Kova, Apr 22, 2012.

  1. Kova New Member

    Apr 22, 2012
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    This is my first post in this forum so I want to say Hi to everyone and I hope to learn and share my experiences with all of you :)

    I opened this thread because I want to modify some behavior to my Ati X550 Pci-e videocard.
    I want to edit the bios to force the card to work with an Horizontal Refresh (VGA Monitor) of 31KHz.
    I'm not crazy (not yet :D), but this mod is necessary for to force the videocard to work correctly with the Arcade monitors (the old 80-90's game cabinets, like street fighter 2, metal slug etc).

    There is a guy on internet that sell a video card (derivated from X550 Ati card) that does what I want to do!
    This is the link: http://www.ultimarc.com/avgainst.html
    In the page above is shown the picture of the ArcadVga 3000, but the "old" ArcadVga2 was exactly an X550 video card!

    In the section "TheArcadeVGA card has the following built-in resolutions:" of the link above are listed all the resolutions available.

    On internet is possible to download the bios of this card but there is a sort of protection to
    avoid cloning (in fact the first version of the ArcadVga1 was reversed!).

    So what I want to do is "simple", I want to know if I can change from the original BIOS of my videocard the LUT where all resolutions are stored.

    I disassambled the code of a X550 Bios (downloaded from this site) with IDA (obviously in 16bit) and I started to reverse from searching all int 10h interrupts to reach to find the procedure of set video mode, but I'm not be able to continue because I didn't find usefully code!

    In the ArcadVga bios there are three "int 10h" instead of two available in all X550 bios that I saw.

    Somebody with skills of reversing bios video could help me?
    Thanks a lot.
    Here it is possible to find the bios that I'm using: http://depositfiles.com/files/gys82xl13
  2. W1zzard

    W1zzard Administrator Staff Member

    May 14, 2004
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    how would that work?
    10 Year Member at TPU
  3. Kova New Member

    Apr 22, 2012
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    If you flash the bios on a generic Ati X550 video card, it loops at the pc boot!
    This is what I read on internet! I didn't try.
    Sorry but I don't have any other info about the protection!
    But if you search for the first version of ArcadVga you could find the instruction to bypass the protection.

    If you compare the two different bios (that I attached) you will see that a lot of new code has been added from the author of the ArcadVga2.
    Ah, the author is a young guy not a company :)

    Bye :)
  4. marvinsaint New Member

    Jun 15, 2012
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    Hi friend,i'm tryind to do this in this moment. I have a company which rentall arcade machines and i am converting all jamma arcades to pc. And the best way is use AVGA from Ultimarc but the price are very expensive to send for my coutry ( Brazil ) .I'm especialist in repair of videogames ( xbox360 ,PS3,etc ) and my task in moment is convert a normal ATI card to AVGA .

    About protections i saw some post in italian site talking about protection of AVGA bios. But today i see something interesting, some people showed a sector of bios which would to be changed .Take a look in this :

    Salve ma questo progetto è ancora valido?
    Sto dando uno sguardo al bios che ho trovato in rete (non posso accedere al wiki di arcade italia) dell'avga2 pci-e x550 (se non erro asus).
    Il bios è datato (da hex view):
    2007/06/03 21:42
    Ultimarc ArcadeVGA X550 BIOS V 1.0

    Io non ho a disposizione un'avga2, ma potrei venire in possesso di una sapphire X550 256Mb pci-e, però (ahimè) non ho ancora un cab su cui testarla

    Ho letto un pò i vari post e test che sono stati condotti, ho letto pure le poche info a disposizione su internet.
    Vedendo il dissassemblato, mi pare di capire che l'autore di ArcadeVga (che spero abbia avuto l'autorizzazione da Ati per modificare il firmware) abbia messo 4 protezioni.
    Se qualcuno volesse testare, potrebbe provare a patchare questi indirizzi:
    (0x7f91) Cambiare da 74F9 --> 9090
    (0x7faa) Cambiare da 7509 --> 9090
    (0x82bd) Cambiare da 74FB --> 9090
    (0x82d4) Cambiare da 7502 --> 9090

    I primi due indirizzi ho visto che sono stati già provati a pag. 5 di questo thread, ma io li userei insieme agli altri 2 (che non mi sembra siano stati mai "studiati").
    Inoltre, ho letto dell'xtal a 27MHz invece che a 31MHz, questo può essere un problema, ma io andrei per gradi

    P.S. non mi assumo nessuna responsabilità , fate un backup del vecchio bios
    P.P.S. Nel caso in cui non dovesse fungere, provate ad invertire i jumper, in questo modo:
    (0x7f91) Cambiare da 74F9 --> 75F9
    (0x7faa) Cambiare da 7509 --> 7409
    (0x82bd) Cambiare da 74FB --> 75FB
    (0x82d4) Cambiare da 7502 --> 7402

    Fatemi sapere

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