Mega-CD real region free on game discs

Never really paid attention and the fact this feature was never really brought to light didn't help either...

The write cycles for a 3.3V version still exceed 100,000,000,000,000. I doubt anyone here will ever flash games through it that many times...

So true. I had some issues using model 2 BIOS on model 1 console. Funny thing is the V 2.00 BIOS for JP model 2 console can eject my model 1 from the menu. Has a button. Interesting...

I can link to where I found the BIOS files if anyone is interested. Guy claims to have permission from the creator to host them.

 

I made the hacks and the links are on the first post ... lol

If you have better filehosts, you can mirror them to your heart contents. Just point people to this thread though so they can read on how to use them.

 

mmmonkey and yes, l_oliveria said it was ok in this very thread. (mmmonkey is hellbelly on page 8, post #142)

 

I got the BIOS from the first page but I couldn't make heads or tails of it. No BIOS.bin files. Just a bunch of .html documents, .txt documents, and other file extensions...

The one from mmmonkey was at least complete .bin files that needed no mods or anything.

When it comes to hardware hacking, I know enough to hang with the rest.

Software hacking is, well...

Lets just say most of what I do even with instructions either dies or takes multiple tries to get right...

 

Hello,
I’m mounting an 27c1024 multibios in my CDX in parallel of the MPR original bios with an switch for activate the ori. or multi


I doubt for the pin connection of original cdx TSOP MPR 40 pin .. I've found different informations contradictory.



It’s the “e-“ in pin 2 or pin 12 in the TSOP ?

I want put the switch in the “chip enable “e-“†of each chip for activate multi or original.
It the good solution ?

modification:
pin to pin mount above original chip, exept:
I unsold pin 2 of original bios (e-?)

Center pin switch in MB pin2 location
Side 1 pin switch > pin 2 original bios MPR TSOP 40 (is “e-“ ?)
Side 2 pin switch > pin 2 (e-) 27c1024 erpom

It’s the “e-“ solution appropriate? Sufficient ? Better with VCC ? or other solution ?

Easier => anyone have make mounting diagram for each solution for mcd like, because I’ve this CDX and also wondermega for modificate. ?

Thank’s for your help and your great works for years

Jacques

 

Solution :

two 10K ohm resistors (brown red orange)
one 2 position 3 pin switch


join one side of the two resistors and connect to +5v connect the other sides of the resistors to the two border pins of the switch
connect the middle pin of the switch to the CDX board /CE pin
connect the two edge pins of the switch one to each bios chip

connect the joined pins of the resistors to +5v


Voila ! Switch is complete !

 

Thank's Oliveira for this solution, I work on it now. I hope I've 10Kohm resistance in stock. Regard's --j--

 

10K is a generic value... you can use also 4K7 or any other value around 2K2 to 22K...

 

Very well, I'll be find good resistances.

I prefer to feel like an idiot, but I need more precision because I didn't understand the whole.

In my little picture you can see the letters point, easier to explain



Either I seriousely doubts for the pins of the MPR TSOP original chip, Are they the same that the 27C10214 ? If not the /CE is in pin 2 or 12 ? And VCC(+5v)

Thank you very much for your help Oliveira.

 

Join A and B connect to +5v
Join C and F connect to BIOS 1 chip pin 2
Join D and G connect to BIOS 2 chip pin 2

connect pin 2 that comes from MD board to point E at switch

 

This can't be more clear for my little brain Thank's a lot.
Jacques

 

Considering the discovery of a secondary boot mechanism for special ROM cartridges on the export MEGA-CD/SEGA-CD boot rom, I discovered the purpose of the copy of the SEGA security program these BIOSes have within them.

And obviously now that I know it better, so I decided to undo the tampering in them.

Because I modified the said security program to simplify the region free hacks, the hidden boot mechanism is unusable on these modified BIOS.

I decided to rectify it by changing the way I attack the problem:

I will use the area where the console regional lock error message displaying code used to sit, injecting there code to set the pointer for the LOGO data already present in the ROM, after the game has ran it's security program, keeping the behavior of the hack, but avoiding damage to the "hidden" boot mechanism this time.

As I got a better grasp of the 68000 instruction set, this time I can do a better, smaller hack.

What this means ? Means that all the non Japanese MEGA/SEGA CD BIOS will change.

Edit:


I found the thread with the original post about the discovery of the hidden boot method. By Nemesis of Spritesmind:

http://gendev.spritesmind.net/forum/viewtopic.php?t=1018

 

I am planning to mount the region free bios in my Sega Mega CD II. I guess i have ground pins 39 (A17) and 38 (A16) on that modell as well?

 

No, because the chips I sell are already the correct size.

 

Thats great, finally a socket friendly chip. Thank you.

 

Bumping this.

As mentioned on a previous page, I have a Mega CD (model 1 - now for my son when he is old enough and can appreciate it....I hope) and Sega CD2 both with multi-bios'. So yes I installed a switch (yes yes boo-hiss).

BUT I also have a Sega CD (model 1) that I repaired from near death (as I mentioned a few times as I am super-proud), that I was about to install another multi-bios into. I have held off though to review this (as I got the Multi-BIOS chips a looonnnggg time ago).

So which would be the best region free bios to install for the Sega CD (model 1), is it still the Japanese version or are they all about the same now?

I would have to get the chips off Bad_ad84 as I don't have a burner.

Thank you.

I have also considered trying to source another lower half of the Mega CD (model 1) case to redo that console with a region free bios, but that would be more of a cosmetic thing.

 

Jap version.

l_oliveira hasnt released the updated one for other regions as of yet. So as per his comments above, the jap one is best.

 

Ok thank you.

 

I am still researching how I go around making the SEGA licence screen be skipped by games which detect it.

There's still two games I have no idea how they detect they're running on a non JP system.

Current method I am considering is a button combo to cause the BIOS to skip the SEGA logo screen (improves compatibility greatly, mind you).

Still using the JP bios is PERFECT as it can run anything (Including the annoying PAL games which check the MEGA drive hardware region flag).

 

Thank you for the reply, this won't be a thing I do tomorrow as I no longer have the disposable income and I am currently bidding on some games on ebay.

I actually bought a spare laser for it (Sony KSS-240A) and of course it is 3rd party (for the paltry $13.50 delivered what did I expect lol!). It reads original discs fine (music and games) but won't read burned media. By burned media I mean music CD's (copies of CD's I own but keep in the car incase some smart ass breaks into it and flogs them) as I don't have any burned games for it. The original laser, which I still have and still works read the burned stuff just fine. Thinking of just going "ah well" and source a genuine laser. Just like to have a spare.