Mega-CD real region free on game discs

Okay, I've finally got the AC adaptor! Having a bit of trouble getting the Mega CD working though, it's having difficulty ejecting and inserting the tray. I think I'll start a new thread about it, rather than clogging up this thread that's suppose to be about the region-free BIOS.

 

hey guys i stumbled upon this thread last night while fixing my sega cd model 1 cd tray stuck open issue. The unit is working perfectly now, so I figured while I had it open i would take a look to see if the bios is socketed and flash-able, and it is. I have a willem programmer PCB50B that i used in the past to revive a CPS2 arcade board that died, and I have a UV eraser. I erased the bios eeprom labeled AM27C1024, and verified correctly in the software that it was cleared.
I took the japanese bios file and renamed it BIOS.BIN and ran the swap bat and checked out the hex in the programmer software and it looks good. I verified again that the chip was fully erased and tried to burn the program but i get a buffer error everytime. I am worried that my TWP is too low or something, trust me i have varified my dip switches are correctly set and my 16bit adapter is installed. I tried it with disconnecting jumpers A19 A20 A21 and no go. Anyone know what I am doing wrong besides using a terrible crappy programmer?

 

Make sure your rom is byte swapped....


On a hexaeditor the header must look like this:

Not like this:

 

hey thanks I made sure to use the swap.bin output file just to be sure my big endian difference was not the issue. I believe I have an issue with my cheap programmer not getting enough voltage even though I am running an extra 12volts 1amp dc external voltage power supply coupled with the lpc port...

I think i might need to source a new programmer or get someone to program the bios on a new chip for me.

Ok thanks for this awesome bit of bios reengineering and if anyone here has my willem POS programmer and knows what I am doing wrong possibly by not messing with TWP and VCC I would be grateful for some input.

Thanks,
mikeosoft

 

para willems suck =/

 

If anyone is interested I have a bunch of 27C4096 EPROMS I can program with the region free BIOS's, you just need to cover the cost of postage and the cost of the EPROM's, there is a small catch UK only thou!

 

Wow I wish you were located in the USA. I'd kill for someone to program me 3 Japanese chips. I'll look in the marketplace for someone who can do it for USA folk. Thanks for being cool and sorry for being on The wrong side of the pond.

 

27C4096 is 4x larger than it needs to be.

 

Yah ... Good opportunity to make the chip compatible with more models as you can put a bios for tray models and a bios for lid models .... Very helpful if you want to make a chip that works for all people:


Wondermega 1
MDJP 1.0
Wondermega 2
MDJP 2.x

Have A16 and A17 pins of the EPROM lifted and pulled up with resistors, then use wires to GND to choose which of the bios you want use.

Like the chip I sent all the way to U.K. for raylyd.

 

Not a bad idea if you want to program a batch that covers all the bases.

I tend to just program "to order" though... and the 27c1024 are quite a lot cheaper

 

l_oliveira is right, you can have four different BIOS's, just select which one you want before powering up. This is how my setup up is, infact I have the Model 1 region free BIOS's EUR/USA/JAP as no one BIOS plays all CD games correctly and for the last 128K I have a modified version of MOD's transfer suite, ideal setup for me. Yeah 1024's are cheaper but I ordered a pack of 10, as I needed 2 and buying individually was way more expensive. So I have 8 x 27C4096 to sell with data of your choice to put on them and I also have 2 x 27C1024 to sell, again with data of your choice, anyone interested just PM me, thanks.

 

http://www.assemblergames.com/forums/showthread.php?39971-For-Sale-Modding-parts-chips-etc

 

Shipping costs from the UK for EPROMs is pretty low and very affordable compared to larger objects.

If anyone prefers sourcing them from an American I'd be happy to offer my services.

 

Its actually same price/cheaper (depending on the destination) to send world wide from the UK than it is internally. Which is just madness.

 

haven't really kept up with this thread, but now that I have an eprom programmer i'm a bit more interested, what is the recommended chip size for this and is any wiring adjustment needed or is it a drop in replacement?

 

27c1024, drop in replacement, make sure its byte swapped (I think the archive has them preswapped for your convenience)

 

So where does the X'eye stand? Bios listed on OP working or not yet?
I don't seem to see any success stories here, but I've got an early model X'eye I need to do some extensive mods on anyhow...

 

It's non working because the currently available dump is suspected bad, devs do not have the hardware for testing and that's all about it.

I was able to test the Wondermega1 bios on a MEGA-CD and fix any problems it had (the Wondermega bios do not work on emulators due
to CDC issues but it works on a real tray model MEGA-CD ...) so I was able to fix it properly.

 

You see craziness like that everywhere... it's cheaper for me to send a package Priority to Eastern Europe (from where I am in the US) than to send the same package to Canada.

 

Is it the matter of dumping the maskrom because the available x'eye dump is bad? if so, I can probably look into pulling the bios off mine and wiring it up to my programmer...