The wait is almost over!

Hi everyone,

A couple of weeks ago, I was feeling comfortable enough to release my next custom bios before 2016. Then I postponed the release date to February. Right now I cannot commit on a release before March. I am sorry about this but you have to understand that it is also frustrated for me! I have been working hard in the next version despite a busy schedule and substantial personal changes.

The good point is that the version 1.032 is “feature complete” and is working properly. I introduced new features and cool customization options. I have only one thing that stops me from releasing my custom bios: the holly check.

As you may know, at boot time the bios is copied from the chip to the RAM and the Holly controler performs some sort of a checksum to determine whether the bios is legit or not. If it is not, the GD-ROM drive is locked and ypu cannot play any game. So far I have been using code (bootstrap) from a beta naomi bios (a beta version The House of the dead 2) in which only a small part of the bios is checked, leaving the rest up for modifications (Thank dknute for the intel and MetalliC for the first implementation!) That is the way I validate my code on real hardware. Then I inject my patches in the retail bios and more or less bruteforce the Holly check. Right now I have to make the bios pass this check, this is the final step. You may ask “why not releasing the bios with the beta bootstrap?”. Well, here is the heck: this “beta” bios does not support the manual reset (read soft-reset) so you are not able to boot milcd and play with boot discs. I patched the beta bootstrap to handle the sof-reset but as It modifies to the data used by the Holly controller to unlock the drive (more precisely the G1 bus) I face the same issue again: the modified beta code has to be altered to pass the Holly validation. So here I am, trying to get lucky! It takes some times (that I will have next week) but I feel confident. I know that it is not because you change kb of data that this step is harder. I was already able to pass the check with a bios that had more 32kb of data different from the original bios. If by chance I can make the beta bootstrap code with the reset pass the Holly check, I will not have to bruteforce any other custom bios. It is definitely worth trying!

In brief, cross your fingers and wait!

6 replies on “The wait is almost over!”

I’m sorry to say, but with no checksumm algo known or bruteforce you cant do what you want.
to get working MIL-CD software full 2MB BIOS with correct checksumm of all 2MB of its data is required. bootstrap from NAOMI HOTD2 will not help…

I am aware of the checksum thing but even with the few information we can have clues about what is in the box. I recently found something interesting, something that seems to be a limitation of the algo used in the Holly. I don’t have enough time to investigate more at the moment though. We will see if it leads to something tangible.

Anyway, I can tell you that the 2mb are not mandatory to boot mil-cd. The lastest build of the next custom bios used a beta bootstrap and can boot mil-cd. Only the reset is not functionnal. That is the reason why I think it’s worth trying to patch & bruteforce the beta bootstrap 🙂

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