NEW Multi Mega/CDX Multibios also info for CD1/cd2

[Jeroi]

I am making a new mod for Multi-Mega mod. I am bringing also new bios chip that is direct replacement for sega bios chip and you will find yourself 3 region mode with single switch.

More info here: SMLMOD

[l_oliveira]

Are you aware that I and another person have actually hacked the SEGA bios for full region free disc playback ?
1 bios = all discs 

[skforty]

You recommend using the hacked JPN version of the segacd bios?  Does it work on segacd -2 top loaders?  Where do i download?  I found your other posts about it, but not where to download.  Thanks!

[l_oliveira]

It's subtly hinted that people can PM for the files... 

It's copyrighted material, you know the drill. I have top loading bios files as well.

And for best compatibility I do recommend the JPN bios, yes.


My modified BIOSes have no SYSTEM checking (doesn't matter which regional setting your console is at) and no disc region checking (It also aways play it's own internal SEGA logo, disregarding the one that is on the disc.)

[Endymion]

The new bios, it does require a chip swap still, correct?

[kendrick]

My understanding is that none of the Sega CD/Mega CD units have writable ROM chips in them, so the BIOS can't be overwritten in place. One way or another you have to replace the actual IC to get another BIOS in there.

[l_oliveira]

My understanding is that none of the Sega CD/Mega CD units have writable ROM chips in them, so the BIOS can't be overwritten in place. One way or another you have to replace the actual IC to get another BIOS in there.

Exactly.  This mod goal was keep the system as close from original specs as it was possible. So since I had an Asian MEGA-CD (tray model) I picked my own BIOS, decompressed the SUB-CPU bios, patched the checks out and put it back. Then I changed the SEGA LOGO code so it would aways display the JPN SEGA logo. While I was at it I removed the MD board version checks.

Result was an 100% identical to original unit but it runs on any mega drive/genesis and boots any SEGA/MEGA CD disc regardless of the region. No holes drilled, even.

[venom4728a]

I sent a pm.  I have a model 1 and model 2 I would like to mod.  Does the Jap bios make the games display japanese language?  After this bios is installed i can play all regions Jap/eur and USA correct?

Thanks for your hard work.

Best Regards
Robert Miller

[l_oliveira]

Only the BIOS screens are affected. So your games will play in english (I believe I already replied this question through the PM along with the link to the files) but I'll leave an answer here as well in case other people search this thread.