Modified Saturn BIOS

MrSporty

New Member
Hi guys , being new to the board i wont take up too much time.

Ive been reading all the hit and miss posts regarding mods and the various incompatibilites and was wondering if anyone else had heard of another solution.

I remember way back in the day that certain suppliers were actually replacing the SMT BIOS of the saturn with a hacked one that had the outer ring protection check entirely bypassed.

Is this just my imagination or did anyone else hear about this ?

MrS
 

mal

Member
IIRC the bios has nothing to do with the security ring. I believe it's handled by some other part of the Saturn.
 

ExCyber

Staff member
I do recall reading about someone who had experimentally modified the BIOS to not perform the ring check. This is entirely possible, but according to all sources I've seen, reading data tracks afterward is not. That is, if you are in control of the host system, you control when the ring check happens, but the CD controller will refuse to read past some boundary (probably sector 15, to allow reading the IP.BIN to verify console/region info, otherwise there'd be no way to know it's a Saturn game before doing the check) until it is done.
 

croft

New Member
Hi :rolleyes:

I am also new to the forum.

Hi to all sega owners worldwide :hehehe:

Great question,

I wonder if there is a way of reversing the modchips data into some sort of cd boot code for the machine.

I can remember reading on the net that the outer track contains no data at all?.

This was from a rep at Sega,The machine doesnt even read it as such,It just recognises its there.

This machine must be the brain twister of the century. :huh

I wonder if its possible to figure out which pin on the chip carries the read commands of the laser.If so shurely lifting this pin away from the track would cure the problem,Or bypassing it somehow.

The outer edge of the disks look holographic and reflect light much like a mirror.

:smash
 

ExCyber

Staff member
I can remember reading on the net that the outer track contains no data at all?
It almost certainly does contain data (cf. the description of the implementation in Sega's patents), but a Saturn program probably can't read that data.

This was from a rep at Sega,The machine doesnt even read it as such,It just recognises its there.
Well, that depends on what you mean by "the machine". Most likely, the H8 microcontroller on the CD board reads (part of) the signature from the ring, then sends a packet to the CD block on the mainboard indicating that it was found.
 

AntiPasta

New Member
Well we know the CD cable pinout, right? Someone tried hooking up a logic analyser to some of the relevant pins and dumping the output while the Saturn's reading the security ring?
 

MrSporty

New Member
You hit the nail on the head there m8 , we need some timed logs of both the CD data stream and the cd mech MCU data stream.

These are the 2 serial streams that get modified by the modchips..

MrS
 
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