SNK Neo Geo AES UniBIOS Install

If you’ve heard of the SNK Neo-Geo, then you really should know about the Universe Bios. Developed by Razoola, many see it as an essential upgrade to their AES console or MVS board.  It’s worth noting that you can only buy the Universe Bios from Razoola, or have it fitted by an installer listed on the official site, please do not purchase one from anywhere else without first checking with Razoola.

UPDATE July 2020 – The UniBIOS is now free, please don’t pay a lot of money for it – you should only be paying for the chip and postage, plus a bit for actually flashing it.  Please check the official download page for more information.  If you’re in the UK, it looks like Consoles Unleashed are authorised to supply chips.

This guide covers the Home AES console, as the existing BIOS chip is soldered to the motherboard.  Most models of the Arcarde MVS boards have the existing BIOS chip already socketed, so you can simply swap them over (although some aren’t socketed and this guide is relevant, or some need an adapter).

If you get the Unibios installed professionally then it will probably have the original bios chip removed and a socket installed. This is the neatest solution and looks fantastic. BUT it’s not easy to do with normal everyday soldering equipment. I practiced on a few old circuit boards and didn’t get on with it.

It is possible to do a DIY install by removing the existing chip and replacing it with a socket, some cut the old chips legs off as close to the motherboard as possible and then use either a desoldering pump or braid to remove the excess solder. I really can’t get the hang of this method, but did read instructions on the official page about piggybacking the new bios on top of the old one so thought I would give this a go.

Here’s the parts, a 15k Resistor, a 40 pin DIP socket and the Bios chip (I’ve put a label over the erase window  it’s unlikely to be erased whilst installed in the console I guess, but better safe than sorry!).

Neo Geo UniBIOS Parts

Once you’ve opened your console up (hidden screws underneath the foam feet) locate the BIOS chip, I then placed the socket on top, test fitting it (I had to bend the sockets legs very very very slightly outwards, but they should be a nice tight fit over the original legs).

Existing BIOS Chip

Test Fitting Socket - Piggyback!

Now the destructive part, you need to snip leg 2, preferably as close to the motherboard as possible. Not too difficult with a pair of decent side cutters. Be VERY careful of the motherboard and any traces that might be near pin 2. If you are unsure which is Pin 2 then check out Razoolas excellent text document for a diagram. Once snipped off, carefully bend the leg outwards so it’s parallel with the motherboard.

Cutting Leg 2

Lifting Leg 2

I case you damage a nearby trace whilst cutting that one, MKL produced this bit of info to help repair it – AES Bios Traces near Pin 2

You can’t really see it, but the photo above also shows that I have added the tiniest bit of solder to each and every leg of the bios chip, it really is a very small amount.

Insulated (heatshrinked) resistor

Test fitting resistor

I thought it would be easier to test fit the resistor before the socket was in place. I insulated it using some heat shrink and then bent the legs into place so that one end goes to the lifted Pin 2, the other end to Pin 40. DO NOT solder in place though, otherwise you may struggle with soldering the socket in place!  For some reason, I opted to not cut the resistor legs to length?!

More test fitting, legs 2 on BIOS and Socket bent outwards

Soldering Legs in Place

With the extra solder in place on each leg it will be a very snug fit for the socket, but it’s worth it because it makes soldering a lot easier and you’ve got 39 legs to solder together! The first photo above shows a test fitting – notice Leg 2 is bent outwards to match the one on the chip. When test fitting the socket, be careful not to let any leg bend inwards.

I then went around each leg with the soldering iron, carefully heating the solder on the old leg up, and dragging the iron up and over the leg of the new socket, if necessary add a tiny bit more solder, but be careful, you don’t want to add too much and accidently solder adjacent legs together.

Soldering Resistor to Leg 40

Soldering Resistor to Leg 2

The first photo shows the end of the resistor is soldered to Leg 40 of the both the old bios and the socket (you’ll also see I need to re-solder leg 39 and that I accidently bent leg 38! oops). The second photo shows the other end of the resistor (I need to trim it!) soldered to leg 2 of the original BIOS chip.  Sorry about the quality of these photos, they were too dark, heavily compressed and taken from the wrong angles?!

Link wire in place


Nearly done now :-) You should be able to see that I’ve soldered a thin wire from leg 2 of the socket onto leg 20, that’s all the soldering done now. You’ll notice that it’s quite close to a game cart, but there’s just about room – promise!

Of course, this is all thanks to Razoola, please show him support and don’t buy a Unibios chip from anyone else (the 3rd party installers on the official site will supply an official chip for you). Please do not ask me to supply you a chip, all requests for this will be ignored.

Summary of Components

  • 1 x UniBIOS
  • 1 x 15k resistor
  • 1 x 40 pin DIP socket
  • some wire