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jmrydholm
Joined: 05 Apr 2005 Posts: 12 Location: Michigan
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Posted: Tue Apr 05, 2005 4:56 pm Post subject: Strange error message |
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Hey all,
I'm getting a strange error message when I try to add certain rom files to the program list in DreamWriter. (This is for the 64MB MD-Pro cart) I get:
"Access violation at address 004CDF90 in module 'mdmtlk'.exe. Read of address FFFFFFFF."
A good example of the type of cart images that do this would be Ninja Turtles: Hyperstone Heist, Konami's Sunset Riders, and others. Is this some kinda protection? I tried various dumps on the two aforementioned games and they did not work. I tried another hacked dump of Castlevania: Bloodlines and that one works fine though. If I sould like a total idiot, mis-un-informed childlike midget, or the so called slang vernacular "noob, newb, newbie, etc." then I must apologize and kick my head through a nearby wall. Any info is appreciated.
Oh yeah and Tototek rules! I love this flash cart! My hat's off to Tomy and the rest of you. -John _________________ 8 bit is groovy. 16 bit rules forever too. Don't argue. |
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deadscreem
Joined: 18 Mar 2005 Posts: 16
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Posted: Tue Apr 12, 2005 2:35 am Post subject: |
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This happens because one of the names stored in the Genesis header is blank. (all spaces) By default Dreamwriter will use the name stored at 0x120. If the name at 0x120 is stored in Shift-JIS (japanese text) It tries to use the name at 0x150. And there is the problem. there are quite a few japanese games that have the first name stored in Shift-JIS than have the second name blank. And also alot of other games which have blank names in both. Dreamwriter needs a valid name to use for the menu.
To fix this you need to hack the ROM to add a english text name in the ROM header. YOu can use a hex editor like Hex-workshop. or one of the many genesis ROM header editors. |
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jmrydholm
Joined: 05 Apr 2005 Posts: 12 Location: Michigan
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Posted: Wed Apr 13, 2005 5:46 pm Post subject: |
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Ah, I see. So what causes the red screen of death? I copied Quackshot, TMNT:HH, and Rocket Knight but all I get is a red screen upon boot up on all of them. They all have name headers too under the menu. For some reason only the first 3 of my dumped ROMS work this time. maybe I'll reformat the flash cart and try again. _________________ 8 bit is groovy. 16 bit rules forever too. Don't argue. |
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Tomy Site Admin
Joined: 02 Aug 2005 Posts: 414
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Posted: Thu Apr 21, 2005 4:00 pm Post subject: |
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jmrydholm,
"Access violation at address 004CDF90 in module 'mdmtlk'.exe. Read of address FFFFFFFF." mean something wrong when you run dreamwriter software. That is your windows problem or some setup problem. If md pro broken, something will like that :
1) Can not detect the cart
2) After flash games, verify error
Of course wrong cables also cause problem. You have red-screen mean checksum error from games. So, you don't have fully flash the games. That mean you need to flash game and verify without error. If you have "Access violation" error, of course you can not finish flash and verify. Please try another pc. Thanks. |
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deadscreem
Joined: 18 Mar 2005 Posts: 16
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Posted: Sat Apr 23, 2005 8:35 pm Post subject: |
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jmrydholm wrote: | Ah, I see. So what causes the red screen of death? I copied Quackshot, TMNT:HH, and Rocket Knight but all I get is a red screen upon boot up on all of them. They all have name headers too under the menu. For some reason only the first 3 of my dumped ROMS work this time. maybe I'll reformat the flash cart and try again. | Red screen of death is ROM checksum error |
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deadscreem
Joined: 18 Mar 2005 Posts: 16
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Posted: Sat Apr 23, 2005 8:42 pm Post subject: |
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tomy wrote: | jmrydholm,
"Access violation at address 004CDF90 in module 'mdmtlk'.exe. Read of address FFFFFFFF." mean something wrong when you run dreamwriter software. That is your windows problem or some setup problem. If md pro broken, something will like that :
1) Can not detect the cart
2) After flash games, verify error
Of course wrong cables also cause problem. You have red-screen mean checksum error from games. So, you don't have fully flash the games. That mean you need to flash game and verify without error. If you have "Access violation" error, of course you can not finish flash and verify. Please try another pc. Thanks. | tomy, did you not read my post? I explained exactly why this happens. It is a problem with DreamWriter not his computer. This happens when the ROM has no English name in the ROM header to use for the menu. If the ROM has only a Shift-JIS (japanese) encoded name in the header and a blank (all spaces) english name, that Access violation error happens. To fix it you have to hack the ROM header with a new engilsh text name. And it wont happen.
What Dreamwriter SHOULD be doing is to autodetect if there is an invalid name (japanese or garbage junk) and give an option to input a temporary name to use for the multiboot menu. |
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SegaDevega
Joined: 14 Mar 2006 Posts: 2 Location: Banffshire, UK
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Posted: Tue Mar 14, 2006 10:10 am Post subject: |
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About the "red screen of death",
Have you been playing around with the ROM, ie hacking or changing it?
Alot of Megadrive games contain routines where every 16-bits of the ROM (after the header) is added together and compared to a "checksum" that is also calculated (and inserted) in the same way when the game was made.
If the two numbers don't add up (which means someone's been naughty) then the game will display a red screen and explode in your face and kill you.
Alot of ROM images are "dirty", which means the checksum will be calculated wrong. There are some good tools on the 'net that will fix them for you. _________________ Want to learn how to program your own software for the Sega Megadrive?
Don't have a degree in electronics or computing?
Don't know sh*t about programming?
Then visit Devega!
www.sega-devega.net |
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jmrydholm
Joined: 05 Apr 2005 Posts: 12 Location: Michigan
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Posted: Thu Apr 27, 2006 7:14 pm Post subject: |
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Here's a new message I get recently:
When running DreamWriter (Genesis) 2.1 after a few minutes or so, I get a small window that pops up every few seconds that reads "MDMTLK: Priveleged instruction." Never had this problem until now. Is there something that could be interfering with the way the cart is read or something? _________________ 8 bit is groovy. 16 bit rules forever too. Don't argue. |
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