Suitable flash chip for custom bios?

[sneeze]

I'm interested in replacing the ps2 bios with a flash chip (and making my own custom bios).

I know it's been done in the past, but I can't seem to find any specific information on it.

So I simply wonder if anyone in here can recommend a suitable flash chip, and has a list of the pinout of the ps2 bios chip?

[jbit]

I'm pretty sure I remember that the PS2s BIOS is authorized before it's booted. So making a custom BIOS would be trickier than just piggy backing the chip and snipping the chip select.

[offonoffoffonoff]

hey jbit,

what do you mean when you say the ps2 bios is autorized before its booted? do you mean theres some kind of validity check the ps2 runs before loading off the bios chip?

I am unfamiliar with the specifics of the ps2 architecture. is there a kernal eprom and a seperate bios eprom? the authorization algorithim might then be on that chip, or somewhere else...

later.

010 010

[TyRaNiD]

There is no _check_ on the bios before it is booted from what I know of cause Sony didn't think it was a suitable target for replacement. Unfortunately I cannot remember the chip in question which is a suitable replacement for the ROM in the ps2.

[Dr.Wily]

A simple question :

I wonder if I replace 10k chip BIOS by a 30k chip. Can I use Ind Exploit on 10k machine ?

[jbit]

There is no _check_ on the bios before it is booted from what I know of [...]

Fair enough, I guess I was told (or remembered) wrong then, sorry for the confusion. :)

I wonder if I replace 10k chip BIOS by a 30k chip. Can I use Ind Exploit on 10k machine ?

Doesn't the independence exploit work on SCPH-1x000 machines anyway? You've just got to be careful about your payload AFAIK.

[Dr.Wily]

10k and 15k BIOS are missing library for execute app through Ind Exploit.

[TyRaNiD]

No 10k/15k/18k are just broken kernels, I have posted previously about how to fix that, but I probably never posted the patch code cause it is Sony copyright code :)

[Herben]

The BIOS is "sort of" authorized.. 18k+(perhaps only v1+) use ROMVER from the BIOS to unlock the drive on startup. That's really only the tip of the iceberg when it comes to making a completely custom BIOS. Also, please don't ask me for specifics on this process as I don't want to piss off Sony.

That being said, I've used M29W320D(T/B) flash chips in PS2 and programmed a modified copy of the official BIOS to it. But that was back in the day before modchips existed that can let you boot ELF files on startup.
These days I wouldn't bother installing a flash chip, the install sucks hard. :)

Unfortunately it seems I don't have my notes from the BIOS pinout anymore.