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CrackLtd
Joined: 05 Feb 2007 Posts: 239
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Posted: Mon Jul 02, 2007 8:43 am Post subject: Who is JSI / Magicom Highrom |
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When turning on a Griffin, an Magicom or SMD800 it always says "(C) 199x JSI" on the screen. Anyone knows who is JSI? Whats he doing today? He's still in the business?
Other thing: The original Super Magicom was not able to load HighRom games. But i know there was a hardware fix consisting of 3 logic ships (74xxx) and a lot of wires you have to solder on the Magicoms pcb. I also can rememberl that you have to cut one or two traces on the pcb. I did these hardware upgrades by myself back in the 90s, but i completly lost all instructions on this fix. Anyone still has these information?
Kyuusaku: You rule! |
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kyuusaku
Joined: 26 Jul 2003 Posts: 941 Location: .ma.us
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Posted: Mon Jul 02, 2007 4:00 pm Post subject: |
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JSI worked for FFE from I think 1988 to 1996-7, his first project was the Griffin but according to him he did part of the original Magic Card BIOS (ie he hacked Bung's BIOS) The guy before him (who hacked the Game Doctor hardware for FFE) apparently went on to make the Sane Ting units.
JSI isn't around anymore and can't be contacted, FFE gave me his email 4 years ago but he never responded. (Same with Fanwen Yang, another FFE employee) If you want to learn a little more about him, look through the SNES scene's few magazine ROMs, one of them has an interview with him.
When looking through Schweino's scene archive I found a Magicom Hirom circuit, but I don't remember what it exactly did, it certainly wasn't too bright. Back then people only sorta understood what the hardware did.
I believe how it SHOULD work if you want automatic switching (otherwise you'd need to enhance the BIOS and add a register) is if the system accesses 40-7D:XXXX or C0-FF:XXXX (HiROM areas), move A[20:16] (address lines) to A[19:15]. The problem with this though is that SRAM would still be mapped to the same area. To fix this you would need to add another circuit which switches the address lines for SRAM decoding (I don't remember the early HiROM SRAM area) and this would need to be held in the HiROM position by a flag set by switching to HiROM areas. The switching can be done with an AND2 (to decode C0) a flipflop (74HC74 to act as a flag) and a MUX (74HC157), this will only support 8M HiROMs because the 157 can only switch 4 bits. If you add another 157, it can switch 8 bits giving you 3 bits left to switch for SRAM decoding. Unfortunately that won't be easy to hack since I believe the logic is inside the programmable EPLD chip. So that may be useless.
How I would do it: I would hack the extension board at the bottom of the unit not the main PCB. I would put a toggle switch to manually select Lo/HiROM. After loading a game, you could just flip to the correct position and press reset, this would solve any problems of LoROM games accidentally triggering the switch to HiROM. My way would need to move HiROM SRAM access to LoROM so the MAgicom catches it, this would need to be done in logic (which I can't give without knowing the HiROM SRAM area)
Another good thing to do while you're hacking a Magicom is add in "SRAM limiting" This will let you play lots of protected games on a Magicom without cracks even needed for SWCs :)
SRAM limiting is done by masking unused SRAM address lines which would otherwise be decoded and detected by the game. Because early copiers didn't have this feature, the games could easily detect that there was 256K of SRAM instead of the proper 16K or 64K or no SRAM at all and know they were copied. You could do this with 4 toggle switches or make a combinational logic circuit to do it with only 2.
Unfortunately, even if you have HiROM support, support for SRAM in HiROM and SRAM limiting, you still don't have FastROM or 32M DRAM which limits you to early games still :) Maybe you could play Final Fantasy V with the mentioned hacks though.
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