Neo-Geo CDZ UniBios Installation

CDZ Unibios

This page covers the installation of the Universe Bios (UniBios) in the Neo-Geo CDZ console. Removal of the original bios chip, installing the larger EPROM chip and testing.


The Universe Bios or UniBios is the creation of Razoola and can be obtained from his official website. It brings loads of features to the original Neo-Geo MVS arcade boards as well as the AES home console. He also now supports a build of the bios for the Neo-Geo CD based consoles too.

The UniBios has a huge feature list. Among its main benefits is the ability to change region, apply cheats, perform system and controller tests and remove censoring in some games.

Commission request

I was contacted by a someone who found my services online, asking if I could possibly install a Unibios in his CDZ console. He wanted the ability to switch region in games to view more english text. This can be done with a simple switch mod, but Unibios can do this without external modifications to the case, keeping the console looking stock. Its a very tricky install and not one to attempt unless you have confidence. It involves lots of rewiring.

When I received the console I tested to make sure everything was in working order before starting. 

CDZ installation

Dismantling the CDZ.

Next the original bios needs removing. its a SOP40 packaged EPROM surface mounted chip. Not as east to remove as the larger DIP chips in the older Neo-Geo’s.

Best practice would be to use a hot air solution, but removal with conventional desoldering method can work well with patience, practice and a steady hand.

Once the SOP40 bios chip is removed, I cleaned the contact pads and got them ready with fresh solder.

Next I had to decide the perfect location of the new BIOS. The original bios is located almost in the center of the motherboard, under the main RF shield. If you want to install the Unibios in a socket, there’s not enough room under there because of the chip height. I decided to try and place the new socket on the right side of the shield and use Kynar wire to extend to the bios location. The wires can then pass through a screw mount that I can safely remove.

The Unibios for the CDZ a pin-for-pin, One-to-one replacement and needs no crossovers in the wiring. One I got all the wires in place on the board, I simply linked them up to the underside of the new socket. I tested for good continuity on each connection as I worked, and again at the end.

With all the connections in place I coated the solder points with hot glue to prevent movement and to stop any wires that may work loose from shorting against the RF shield or other components. The Bios chip is installed and located to the right of the CD-Rom as intended.

Now with the Unibios in place, I can move on to testing.

Testing and Setup

Upon booting I needed to select the region and cosole type. Selecting Top-Loader will stop the CD-Rom working correctly on the CDZ. Other than that I could get straight into testing some games.

I selected a Japanese copy of King of Fighters 94. All the ingame menu’s now show in English. I also tested the cheat capability of the Unibios. Everything seems to be working correctly.

So that was a UniBio installed in the CDZ. Done.


“This is/was my CDZ and when I got it back its better than I could ever imagined. Neil your communication, price and turn around was amazing and Im so appreciative of your work! Thank you so much! MJ”

Thanks for reading, and please get in contact if you need a UniBios installing in your Neo-Geo CD, CDZ, AES or MVS.

Please remember! is an official third party installer of the Unibios (UK). Getting one from from an unapproved dealer means your chip is counterfeit and not eligible for upgrades.  Please see Universe BIOS home page for more info.

8Bitplus 2017

3 Responses

  1. NeoGeoLad says:

    How much (if any) is the improvement on load speed on the CDZ?
    I have looked around online, and haven’t really seen any mention of it.
    I believe Raz’s notes on the CD unibios claims there’s some tiny improvements to the top loader; so I was curious. Thanks!

  2. I was told about Neil on the Neo Geo forum. Wow such great service doing my CDZ and a fast turn around. A* and I would really recommend Neil to have work done. Now I won’t need to learn Japanese for a lot of these games lol

  3. Matthew Jenkins says:

    This is/was my CDZ and when I got it back its better than I could ever imagined. Neil your communication, price and turn around was amazing and Im so appreciative of your work! Thank you so much! MJ

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