Mega-CD real region free on game discs

If you're talking about the SEGA-CD model 2 bios which keeps playing the music from the demo mode at the dashboard screen, that's a SEGA BUG it had even before me hacking it.

 

Will something like this be able to burn the chips?
http://cgi.ebay.co.uk/TOP2007-unive...t=BI_Control_Systems_PLCs&hash=item587f19108e

And what types of chips should i use?

 

Just wanted to say thanks for all your work on these bios'! Hopefully someday I will get around to installing my own and enjoy proper region free on segacd

 

if you aren't planning to flash alot of eproms you might be better off just buying a preflashed chip rather than a programmer

 

It seems like a good thing to have I don't know much about it and i'm looking for the one best suited for retro consoles.

 

Will the same thing be possible to do for the Sega Saturn (region free bios)? My Saturn currently works with a 3pos. switch and it works just fine, but imagine not having to have any switch at all

I know the ultimate mod gets rid of switches but you still have to press the reset button to change region. A totally region free Saturn and a modified ultimate mod that only switches between 50 and 60Hz. That would be cool

 

Possible? Yes for sure but I don't think anyone has publicly released a hacked BIOS to do just that. Hell I'm not even sure if an applicable replacement chip is available or not, at least one that can just be piggybacked onto the existing chip.

 

Yeah I don't seem to recall anyone releasing any type of universal region bios replacement for the saturn either. I assume an action replay is outside of what you want

 

I wasn't sure what you meant at first but now that i looked into it i realize there are different bios chips used in the Saturns.

Mine is the very first model 1 saturn released in Japan so it has a bios chip the same size as the Mega CD. This isn't my picture, but notice the socketed chip here:
http://members.optushome.com.au/currypuff1/protptype/saturn_proto6.jpg

Mine isn't in a socket so the guy who took that picture must have switched this bios at some point...?

And here is the motherboard of a newer model Saturn and yeah you're right, the bios chip on that one is clearly of another type:
http://i685.photobucket.com/albums/vv218/mac-de/console%20motherboard/SATURNBOARD.jpg

Seems like a lot of trouble creating a multibios for just the Model 1 then. That, and i was planning on replacing this Saturn with a newer "This is Cool" model at some point, which makes it even more pointless :/

Yeah i'm really not into the Action Replay as it not only removes the possibility of using a memory card but also takes noticeably longer to boot. Totally regionfree and switchless mods are the coolest imo

 

Do any of you have one of these bioses for sale?

 

Nope but I can link you to them if you intend to burning a chip with them for your own use.

For free of course ... :shrug:

 

Okay, so I've been playing around with reverse-engineering the Mega CD firmware, and I've found the routine that checks the disc's region. I could just modify the subroutine to check for key x when it is region x, key y when it is region y, etc. and satisfy the game disc no matter the region

 

Please do. I've been wondering about buying an Eeprom burner for a while anyway

My MegaCD 1 suddenly died today or maybe some time ago. I was entering the Everdrive Info screen and there it said I had no CD Rom attached. WTF I thinked and tried starting the console without anything in the drive. Nothing appeared on the screen

I'm using Arakon's multibios and therefore tried various switch settings to see if the results were different.
I also replaced the power supply-board with another one I have from a defective unit just to be sure that's not the problem. Didn't help either.

I tried another MegaDrive just to rule that out but of course the results were the same.

I noticed that if I keep turning the MD on and off the READY and ACCESS lights on the MegaCD sometimes lights up for a second and the european/american bios background appears but no logo or sound, and it doesn't work of course.

Is this a dead Bios or something much worse?

No big deal if it's the bios as I want to replace that anyway with the new kind.

 

I know it's slightly off of the main topic, but it would be nice if someone released an open sourced implementation of the OP's method for patching sega cd isos since it would allow mac/nix users access to conversion. afaik there is no reliable app for them to use?

 

Basically, a quick explanation of what I did:

On the SUB-CPU BIOS, an conditional jump to the fail condition of the security code compare is skipped. This hack was developed by "Raq" of spritesmind.net.

The SUB-CPU BIOS is then CRC fixed, re-compressed and put back on the image.

As for the main BIOS, I noticed that calling the code that displays the LOGO with incorrect data causes the console to crash.

Raq's solution was NOP-out the hook on the BIOS that calls the logo routine if the disc region was wrong. Similar than what Datel's CDX cartridge does.

So I just found an unused copy of the security data on the PAL and NTSC export ROMs (SEGA/MEGA CD units for USA and EU) then patched the SEGA logo hook to display the SEGA logo from the ROM instead of the one on the disc. For the Japanese one I just found a small empty area and dumped the small chunk of data there and "reworked" the code in a way that it would be called after the game's LOGO code, overwriting it with the right data.

Result is that the ROM aways display it's own internal copy of the SEGA LOGO instead of the one that comes on the disc.

No code on the disc need to be changed and game runs as intended. :thumbsup:

 

I'm hoping this hasn't been covered here or on the thread at sega-16 (which I seem to be having trouble finding atm) I'm curious as to why Sega CD Model 2 USA hasn't been modified? It seems like just about everything else has been modified all ready. I've been looking up methods to region free the Sega CD and this seems to be the method that comes up over and over again.

EDIT: Whoops just did a little more reading and it looks like l_oliveira is working on it all ready guess I will wait patiently.

 

I hacked the BIOS files in December/January I just didn't upload due to copyright concern by forum moderators. Anyone interested is free to PM me regarding the files.


The only BIOS I hacked and could not test if it's working properly was the X'Eye BIOS. All the others were tested on the real hardware.

I have hacked BIOS for:

MEGA-CD (JPN) model 1 tray (recommended bios for tray models)
MEGA-CD (JPN) model 2 lid (recommended bios for lit models)
SEGA-CD (USA) model 1 tray
SEGA-CD (USA) model 2 lid
MEGA-CD (EUR) model 1 tray
MEGA-CD (EUR) model 2 lid

JVC Wondermega MODEL1 with lid motor mechanism (Tested, works fine)
JVC Wondermega MODEL2 without lid motor mechanism (untested, see X'Eye)

Multimega (EUR)
CDX (USA)

Laseractive (USA)
Laseractive (JPN) (both untested, only CD-SUBCPUBIOS was patched and supposedly MEGA-LD discs are region free)

X'Eye (same hardware as JVC Wondermega model 2) not working atm, might need a bios redump.


The patches also disable hardware region checks so you can have a country switch installed on your mega drive/genesis console and it will not affect the CD-ROM unit.

Edit:
Laser Active cannot be modified due to the way it detects CDs inserted. It uses the LD bios to figure out if a CD was inserted AND it does enforce region even before the CD bios is loaded... :shrug:
Because I do not own a LaserActive I cannot test patches so I won't dump any more work (and the patience of the person who were testing it with me) on this project.

The X'Eye/Wondermega 2 bios also has problems I would gladly debug but again I do not own a Wondermega2 to test it. And I was able to test the Wondermega 1 bios only because it works on a standard MEGA-CD.

The Wondermega2 bios does not. :shrug:

 

So you can use the regionfree EU Bios even with your console in 60Hz? The original EU Mega CD would complain if powered on while the MegaDrive was in US mode :/

Any thoughts on my MegaCD suddenly not working anymore? Perhaps it's caused by bad soldering?

 

I only recommend the Japanese BIOS because it plays all games ...

The PAL bios has timming issues with NTSC video modes, which causes some glitches and flickering on the title screen logo animations. Nothing serious though.

Again I recommend Japanese BIOS for 100% compatibility.

So an MD-CD1 bios for tray models and MD-CD2 bios for lid based models.

 

Why doesn't the US bios play all games? I wouldn't mind the Japanese bios if I could switch the menu language to English. Very confusing managing save files in the JAP bios :/