Genesis Plus GX Wide now available for Libretro/RetroArch!

heyjoeway has made a custom fork of Genesis Plus GX with experimental widescreen (16:9) options, called ‘Genesis Plus GX Wide’. We now offer this version on our buildbot, and you can download/install it right now on RetroArch for most platforms!

Available for:

  • Android (on Play Store it’s available on Plus only)
  • macOS
  • iOS
  • Linux
  • Windows
  • 3DS
  • Switch (libnx)
  • GameCube
  • Wii
  • WiiU
  • PlayStation Vita

How to get it

First, make sure you update the Core info files. To do this, go to Online Updater, and select ‘Update Core Info Files’.

There are two ways to install and/or update the Genesis Plus GX Wide core:

a – If you have already installed the core before, you can go to Online Updater and select ‘Update Installed Cores’.

b – If you haven’t installed the core yet, go to Online Updater, ‘Core Updater’, and select ‘Sega – MS/GG/MD/CD (Genesis Plus GX)’ from the list. It will then download and install this core.


This is an experimental feature right now. Some games might already output nicely with widescreen, while others will likely require patches to display properly.

It works only on Sega Genesis/Mega Drive games, and not Sega CD/Mega CD games.

How it works/how to use it

To use the new widescreen feature, go to Quick Menu -> Options.

Extra columns to draw in H40 for widescreen
This determines how many extra columns to draw for a widescreen aspect ratio. ‘0’ means no extra columns will be drawn.

In the previous version, this was always set to 10. Now, you are able to tweak this setting. Some games will require a value lower or higher than 10 to display properly, and some games allow you to set it as high as possible.

Let us run down the list of some games and what the best possible configuration for them is:

Ecco The Dolphin 1/2: Set this to 22 (or lower depending on your preference). See screenshot here. (See default 4:3 image here).

Thunder Force IV: Set this to 22 (or lower depending on your preference).

Streets of Rage 1/Bare Knuckle 1: Set this to 18, minimal pop-in (see screenshot here). Set the value lower to eliminate it altogether at the expense of a reduced field of view (See default 4:3 image here).

World of Illusion: Set this to 18 (for minimal pop-in). Set the value lower to eliminate it altogether at the expense of a reduced field of view.

Thunder Force IV: Set this to 20.

Virtua Fighter 2: Set this to 18. See screenshot here. See default 4:3 image here.

Special instructions for Sonic The Hedgehog 1/Sonic CD widescreen

Sonic The Hedgehog 1 runs well in widescreen but requires you to patch the ROM first. Thankfully, heyjoeway made this rather easy for the user to accomplish. Go to this site here and select your ROM file. It will then spit out a modified ROM with proper widescreen modifications.

With the patched version, you can set extra columns to as high as 12. Any more and you will run into the limits of the game’s plane sizes and see pop-in on the right side of the screen.


Introducing the RetroArch Open Hardware project

So ProjectFuture finally materialises! From the beginning, we have been unsatisfied with the general state of the retrogaming scene when it comes to being able to dump and play your own legally bought game cartridges. Solutions exist like the Retrode. There are some big issues with them though that limits their viability as something an average consumer can just buy readily off the shelf:

1. Super expensive.
2. No longer in production/out of stock
3. Rights to the product changing hands between sellers/store owners
4. Because of 3, usually one or two stores can only sell them.
5. The specs are closed so only a select few can assemble and sell them, limiting the ability of DIY homebrewers to make their own device.

While as a general rule of thumb, developers will always tell people to dump their own game cartridges, in reality there is nobody stepping up to the plate to make this either affordable, to integrate it well with existing software, or to make it possible for your homebrew hardware maker to easily build his own.

RetroArch Open Hardware is our attempt to shake up this sector of the retro games market, and our effort to revitalize the DIY market and shift it away from proprietary solutions. Our first Proof of Concept hardware device is an N64 cartridge adapter that you connect to any device with a USB Type-C cable. It will be relatively cheap to assemble and much faster than any existing competing device out there that does the same task.

RetroArch Integration

We have some high-level goals we aim to achieve with this project. We want seamless integration with RetroArch. When you attach this to RetroArch, it should be hopefully as simple to play the game as it is on a real game console when you plugged in the cartridge. That’s the level of integration we are aiming to achieve with this project, and none of the existing solutions out there really fit the bill.

When we mentioned before that we want RetroArch to be its own game console, we pretty much meant it. And being able to take your own game copies with you and run them with RetroArch seems like an obvious next step to take.

We have come up with a completely custom and lean design so that the person aiming to build this for themselves in DIY fashion will be able to build these relatively cheaply. We are convinced the transfer speeds are far in excess of any other similar product out on the market right now, which is just as well considering the biggest N64 game out there is 64MB in size.

The current transfer speed that we are achieving is ~4MB per second on a prototype device. Our target is a transfer speed of approximately ~ 4.5MB per second give or take.

In addition, Switch dock support will be there from Day One, working out of the box.

How does it work?

Attach it to any device and it will mount itself as a Mass Volume Storage device, mapping the cartridge as a bunch of files on the filesystem.

You insert the N64 cartridge into the cartridge reader and you connect it to a PC (or some other device) with a USB Type C-cable. The device will then map the contents of the cartridge itself as a Mass Storage device volume. EEPROM, Flash, ROM, and SRAM are mapped as separate files on this volume. (*)

Playing the game should be as easy as just loading the ROM from this device. So already even without the aforementioned RetroArch integration, it already works. But our hope is that with the RetroArch integration, we finally get the promise of a true cross-platform game console where you can take your games library with you, whether it’s digital or physical, and just use it across the devices that you already have RetroArch on. This is the dream and promise we have been slowly building towards – the power lies in the user’s hands, not that of any corporation or organization.

* – This might be subject to change. We are still considering whether to change this to a dedicated protocol to allow using cartridge hardware in an emulator core without just reading all of the cart as one big contiguous ROM file.


This project has been ongoing now for the better part of a year. We have some internal prototypes and so far we can definitely confirm high success rates with our own cartridge collection. SRAM support already works in the firmware, but no EEPROM/FlashROM support yet. Your SRAM should work as long as your SRAM battery is not dead yet anyway. Some of these cartridges are over 20+ years old by now after all so an SRAM battery being dead is not an unlikely prospect at this point.

Some cartridges will need their cartridge connectors cleaned in order to work properly with this device. It’s a common problem among N64 game preservationists that I’m sure should not be news to anyone at this point.


I’m sure there will be many questions in response to this article. We will remain tight lipped for now until we feel the time is right to release more details. We hope that RetroArch Open Hardware will be a contagious project that will see many contributors and participants working towards one common goal – being able to interface with the games media they’ve bought for all these decades and just being able to make it work with the software they’re already using without having to buy new closed-spec proprietary devices that lock you out of the software you’re already using. Free software is one thing, but it’s only as good as the hardware you’re running it on. Consider this our valiant effort of trying to get both sides in order.

For now, here is a gallery of screenshots to a few of our prototypes, brought to you by Sasa and m4xw.