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PostPosted: May 23rd, 2008, 10:46 pm 
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Joined: May 16th, 2007, 7:08 pm
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Anyone can give me guidelines for dumping this IBM-PC clone's BIOS? (actually, THE FIRST legal clone. By legal I mean it has it's own BIOS and I/O map.)

The BIOS is socketed (good thing)

The PROM chip used says: (the * is the Mitsubishi logo)

"SANYO-55X-NO-1
* M5M2364-171P
843600"

I guess that info is useless if there exists a dumping method that does not involve PROM manipulation. Centronics printer port is available, but RS232 is not. (weird huh..)

If memory map is neccesary I can post it. Also any I/O address and/or interrupts. (all of it is present in the manual)



That's it. I you can help with ANYTHING, it's really appreciated!


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PostPosted: May 24th, 2008, 12:48 am 
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Joined: May 20th, 2008, 3:41 pm
Posts: 62
For the real IBM PC's, you can 'dump' their BIOS with the MS-DOS 'debug' command, by reading the specific memory range with it.

C:\> DEBUG

-N MYF000.BIN (resulting file will be named MYF000.BIN)

-R BX (set BX=0000H/CX=8000H as count of bytes to write, 00008000H = 32K)
BX 0000
:0000
-R CX
CX 0000
:8000

-M F000:0 8000 0100 (copy 32K bytes from F000:0 to offset 0100 in local segment)

-W 0100 (write from offset 0100 in local segment)
Writing 8000 bytes

-N MYF800.BIN (resulting file will be named MYF800.BIN)

-M F800:0 8000 0100 (copy 32K bytes from F800:0 to offset 0100 in local segment)

-W 0100 (write from offset 0100 in local segment)
Writing 8000 bytes

-Q

C:\>copy /b myf000.bin+myf800.bin final.bin


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PostPosted: May 24th, 2008, 3:24 am 
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Joined: May 16th, 2007, 7:08 pm
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thank you very much! I'll see how to do it.. first I hope debug is included in the version of SANYO-DOS I have..

Then I'll have to look the size of the bios, as i'm not sure its 64kb, probably even less than that. Probably 32k. Well, I could dump 64k anyway..

Nothing to do with the BIOS:
Today I replaced the Intel 8088 with a NEC V20. cool speedup. I realized that there's a 62-pin expansion connector and I would like to attach a 10mb HDD. I wonder if it's possible..

Probably will start a page or something detailing the inner workings and stuff of the MBC-55x, along with photos of the ripped-off thing.


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PostPosted: June 11th, 2008, 3:52 am 
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Joined: May 16th, 2007, 7:08 pm
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I managed to dump the MBC550 BIOS. I guess.

-N MBC550.BIN
-R BX
BX 0000
:0000
-R CX
CX 0000
:2000 <- 2000h = 8192bytes, the 8K of ROM the MBC550 has.
-M F000:0 2000 0100
-W 0100
Writing 2000 bytes <- I don't really understand this. Why it says 2000 bytes (showing the number in hex) when in reality it writes 8192 bytes?
Now the problem resides in getting the file OFF the Floppy disk xD

I guess I just have to get the 286 started (hope it works OK) and transfer the file to a 3.5" 1.44mb floppy.


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