Sunday, February 11, 2018

Super Nt Review - The Ideal FPGA Console?

In the four months since the announcement of the Super Nt, there has been a lot of anticipation over the final product.  Will it ship on time?  Will it be as good as the Nt Mini?  Is it worth the money?  Can I put my original hardware away?  Now that I have had mine for about four days by the time this blog entry posts, I can try to answer those questions and give my own impressions of the system.

Enclosure & Accessories

Simply put, the Super Nt's plastic enclosure is a minimalist work of near-perfection.  The rounded edges are friendly and the Analogue logo is round and not loud.  The console weighs at 1.16lbs or 525g without cartridge or cables attached.  Sometimes weight can be an suggestion of the quality of a product and that suggestion holds here.  The bottom is almost totally covered by a rubber mat to keep the console from slipping.  The separate start and reset buttons are a big improvement over the single start/reset button of the Nt Mini.  They are a clicky when you press on them, which is unusual for momentary switches.  However, the resistance of the spring has a benefit in that you are unlikely to trigger a reset or a power cycle by accident.  The controller ports are a moderately tighter with official SNES controllers than the Nt Mini's controller ports with official NES controllers.

Which one would your flatscreen prefer?
I might point out that the LED is not in the middle and breaks the symmetry of the console, but the LED on the SNES and SFC were not in the center either.  The hole on the Nt Mini was too small in my opinion to do any useful effects with the LED, but in the Super Nt it is large and bright enough so that color cycling effects are neat even if you do not have the Clear enclosure.

Speaking of the Clear enclosure, there has been some upset in the community because the artist's rendition of the console from October, 2017 looks much more translucent than the product that was sold and shipped.  The same plastic is used for the matching 8bitdo wireless controller.  Many people have said that the Clear enclosure looks better in person than through photos.  One Youtube reviewer complained about the visible adhesive bubbles in areas where the sticker surrounds the cartridge slot and buttons.  Those bubbles are not visible in the non-Clear enclosures.

The cartridge slot has quality plastic dust flaps.  It is easy to insert cartridges, but removing them will require much more force than an original Nintendo SNES cartridge connector.  The cartridges wobble more than in an original SNES, which can be a bit troublesome when it comes to Super Famicom or PAL SNES carts because they are thinner at the bottom.  US SNES cartridges have a more uniform thickness due to the two ridges which are on either side of the label on all cartridges.

The Nt Mini used a generic power supply and HDMI cable.  The Super Nt comes with a USB cable, an HDMI cable and a Power Adapter that has the Analogue name or logo on them.  The Power Adapter is rated for 5V/2.1A (only 2A is required, so your smartphone's supercharger AC adapters should work).  The power draw of the Super Nt and sn sd2snes cart was measured around 666mA, so there is plenty of juice for the more power-hungry add-ons.  After lengthy play the console is barely even warm.  The HDMI cable that comes with the Super Nt is thinner than the Nt Mini's but is 4.5 feet long, about 1 foot longer than the Nt Mini's.  The Super Nt's Power Adapter cable is about the same length and only slightly longer than the Nt Mini's.

While it may have been better for Analogue to have used a USB Type-C connector for the power supply, the micro USB connector seems properly supported by the PCB and enclosure, it should not break off unless you treat it poorly.  Ditto for the HDMI port.  Kevtris recommends using the official cable because cheap cables have higher impedance which can drive down the amps that will actually be received by the console.

The console comes with a double-sided three page Quick Start Guide.  This guide tells you that you should go to to download the User Guide.  The User Guide does a decent job of giving you an overview of the menu.

Outside the well-constructed box, (which was shipped in bubble wrap surrounded by wrapping paper), is an envelope containing a printed box for Super Turrican Director's Cut.  You have to tear open a strip on the back of the envelope to get to the box.  The box is nice but the back face of the box is printed upside down compared to the front face of the box.

Video Menu Options

Many of the Menu options are self-explanatory or their effects can be easily be seen.  In the Video Menu, the Advanced Mode unlocks additional options.  My favorite way to play the Nt Mini is to use a 6x/5x at 1080p, and the Super Nt is no different.  To achieve a 6x/5x scale in 1080p, you set the width to 1536 and the height to 1200.  Unlike the Nt Mini, which used hexadecimal values, the Super Nt uses more consumer friendly decimal values.  You can press the start button to get to the appropriate values more easily than remembering pixel counts.

Super Nt Menu
Also, the Super Nt is not limited to hard 4x, 4.5x and 5x vertical height choices, you can adjust the scanlines between 960 and 1200 by single scanlines.  However, even though the Super Nt can generate 1200 scanlines, it can only display 1080 lines.  My 1920x1200 LCD monitor will have windowboxing as a result.

HQ4X Scaler
While most SNES games use a resolution of 256x224, some use a resolution of 256x239.  The 6x/5x scale gives the equivalent resolution of 256x216, so there will may be some information cut off the top and bottom.  You can use the vertical position slider to adjust the screen to minimize cropping of important elements.  If you must see every active pixel, then consider using a 5x/4x scale.

6x/5x Scale
The NES and SNES canonical scale is 8x/7x, and the Super Nt has this option.  However, because the Super Nt cannot put out a 2048x1680 picture, you will have to use the interpolation features to avoid ugly pixel scaling.  Intepolation adds softness to the image but it will hide the ugly pixel resizing of non-integer nearest neighbor scaling.  I think you will probably agree with me that the interpolation is done extremely well here and well worth the slight reduction in sharpness.

8x/7x with Horizontal Interpolation
The buffering modes are also new to the Super Nt.  The Zero Delay buffering mode eliminates all latency by reducing the system speed slightly to output an integer 60fps.  With Zero Delay, the controller ports are read exactly when they should be on original hardware and each frame is processed in real time.  The Nt Mini only has Zero Delay.  Zero Delay ensures that the only source of lag is the display.

The Super Nt has two additional buffering modes which were only seen in some of the Nt Mini cores.  They both have the advantage of processing the SNES system speed internally at 60.0988fps but must interpolate that to the 60fps output by HDMI.  The Super Nt cannot output 60.0988fps via HDMI.

The Single Buffer mode adds only minimal latency at the cost of screen tearing (a wobbly line crawling up the screen every ten seconds or so) while the Full Buffer mode eliminates the tearing but adds up to one frame (16ms) of lag.  Single buffer and Full Buffer are the equivalents of double and triple buffering.  Speedrunners can use the Single or Full Buffers to get times that will be true to the original hardware.  The 60fps of the Zero Delay mode makes the video 1 second behind every 10 minutes compared to original hardware.

1.40 RGB Gamma (equivalent to former "Gamma Boost" option)
Most people seem to indicate that scanlines are better done in 720 than 1080.  In 720p, usually every third line is darkened, and in 1080p, its every fourth scanline.  The awfulness comes in 4.5x mode, where the scanlines are uneven.  Avoid that if you use scanlines.  The Hybrid scanlines option is one kevtris borrowed from the UltraHDMI and it is intended to give a scanline look closer to a consumer-grade CRT.  PVM and BVM CRTs give thicker scanlines than arcade monitors and consumer CRTs.  The Hybrid scanlines are slightly thinner than Normal scanlines, but vary in thickness.  Lighter areas of the screen have more prominent scanlines than darker areas with the Hybrid scanline option.    The Gamma boost option can be used with or without scanlines, with the intent to give a gamma curve similar to CRTs and generally brightens up the image. This can be useful in games that use a lot of darkly colored graphics.

Hybrid Scanlines, Vertical Position Adjustment to 40
My Life in Gaming did a typically excellent video on the Super Nt's capabilities.  I think it is a must watch for everyone who buys this console :  DF Retro also did a fine video demonstrating the various options, watch it too :  I am indebted to them and other Youtube reviewers and users on the AtariAge and ResetEra forums for their comments and insights.

Audio Menu Options

The audio menu only has a couple of options.  The -3db Output Cut option reduces the Super Nt's output volume.  It is there because the default 0db causes the DAC on some monitors to clip.  The cartridge audio option adjusts the volume that comes from an sd2snes or either Super Game Boy.  I found that a 128 setting keeps a good balance between internal and external audio.  By default Cartridge Audio is not enabled because it can add unwanted noise where it should not be present.

The Super Game Boy, unlike the Tristar Super 8 (NES), Super Retro Advance (GBA) and Retro-bit RetroGen (Genesis) actually interact with the SNES instead of just using the SNES for input and power.  It sends its stereo audio through the cartridge, but it is a noisy signal.  In quiet or silent areas you can hear the sound of the CPU working.  The Super Nt cannot generate GB audio because it has no way to find out which audio registers are being accessed.  It has to digitize the analog audio from the SGB and compared to the clean internal audio, the results can be jarring.  Nor can it fix the faster audio playback speed from the SGB.

The Nt Mini can simulate the GB and GBC with the jailbreak cores.  So if you want to play non-GBC exclusive games, which is the better option, the Nt Mini or the SGB2 running through the Super Nt?  The screen height and width can be the same with both consoles.  Use a 5x by 5x for the SGB in the Super Nt for square pixels like a true DMG Game Boy.  The audio is far crisper and cleaner out of the Nt Mini, but there is one known audio inaccuracy as detailed in my last Nt Mini blog entry.  The Nt Mini cannot play Pinball Fantasies and its cores do not emulate the RTC of Pokemon Silver/Gold/Crystal and other games.  The Super Nt can play those games and use an RTC from a real cartridge or as implemented on an EverDrive GB X7.  The Nt Mini can't do any SGB features, not even borders, while the Super Nt can do them all.  The Nt Mini in the GB core cannot change the palette colors and can change the palette in the GBC core only as allowed by the GBC BIOS.  As far as latency goes, between the latency that the SGB adds to read the SNES controller adjust frame rate to match the SNES's and the Single Buffer mode of the Nt Mini, the latency battle is probably a wash.

In order to switch games with an SGB and an EverDrive GB, you must perform a power cycle on your Super Nt.  Switching to one of the internal games won't work.

The Super Nt samples audio at 32KHz internally and interpolates it to 48KHz.  All HDMI receivers must accept a 48KHz signal but there are no guarantees about a 32KHz signal.  Some NES HDMI clones sample at 32KHz and fail on some TVs.  The SPC700 ideally samples audio at a pure 32KHz, but because Nintendo used ceramic resonators instead of a crystal on its boards, they tend to sample audio at a slightly higher or lower rate.  Ceramic resonators are cheaper than clock crystals but are less precise.

Extra Features Menu and Other Options

The original SNES can display 32 sprites per line, the Super Nt allows up to 64 sprites.  Sprite flicker on the SNES is not nearly as prevalent as it is on the NES, but this option should virtually eliminate sprite flicker entirely.

Mode 5 & 6 Interlace disable: disables interlace except for high-res modes.  This actually does not disable interlacing in Modes 5 & 6, it disables interlacing in Modes 0-4 & 7.  This option was present for the game Ranma 1/2: Chounai Gekitou Hen, which sets interlaced mode for no good reason.  The games Air Strike Patrol, Power Drive, RPM Racing and a particular sequence in Chrono Trigger were designed to use interlaced mode (512x448 resolution) for some or all of their video.  

Pseudo-hires Blending: blends pseudo hi-res modes (512x224 resolution) for proper transparency.  Known games to benefit from this option are Jurassic Park & Kirby's Dream Land 3.

The Boot Delay can be set from 0-10 seconds.  This can be helpful if your TV or monitor is slow to adjust to new input.  It can also be especially helpful for avoiding synchronization issues when capturing video.

One feature that the Nt Mini has and the Super Nt cannot is that you can start the Nt Mini via a controller button combination (start + B or start + A depending on the controller).  This is because the Nt Mini has a special processor to keep controller port 1 powered and to detect reads from it.  When the Super Nt is off, it is really off.  It is also extremely unwise to try to hot-swap cartridges, turn the system off before changing them.

Super Turrican Director's Cut and Super Turrican II are available from the main menu and can be started at any time.  Super Turrican DC was the original 6Mbit/768KB version of the game that was intended to be released, but the publisher forced the developer to cut the game down to fit on a 4Mbit/512KB cartridge.  To get it down to size, the developers at Factor 5 had to cut out graphics, music, sound effects, weapon features and an entire level.  Interestingly, Super Turrican and its sequel are among the few SNES games to support Dolby Surround Sound, but that feature may be lost as the sound is transmitted through HDMI.  As bright, colorful games that are easy to play with great music and sound effects, they are good choices for pack-in games given the limited choices available.

Firmware Updates and Miscellaneous Observations

See here for official firmware updates :

Despite what Analogue's official instructions may say, the SD card you use to update the firmware on the Super Nt need not be the only file on the card.  It just has to be in the root directory of the card and be the only Super Nt firmware file in that directory.  Just insert and wait. Flashing firmware will reset the console to the default settings, so plan accordingly.

For the games that are intended to use interlacing, the Super Nt addresses it by using combing to deinterlace the frames.  This gives "mouse teeth" artifacts, but the only instances I could see it easily were in the gameplay sections of RPM Racing and the Ramna 1/2 game.  RPM Racing is a lousy game and Ramna can be fixed as indicated above.

The Super Nt's works with all special chip games.  Kevtris removed the Super FX and SA-1 chips and put them on test boards to better learn how they interacted with the base console.  The FPGA is an Altera Cyclone V A4 which has a maximum voltage compatibility of 3.3v.  Kevtris put logic level transceivers between the console and the cartridge slot to convert 3.3v signals to 5v signals and vice-versa.  This ensures reliable communication without risking damaging expensive carts or the console.  The Super Nt should work with the 3.3v flash reproductions that are currently being sold by companies like retro-bit and Columbus Circle without having the risk of killing your original hardware.  The FPGA does not care if the flash used is 3.3v, but your 1Chip SNES will.

Confirmed Working Peripherals

Super Game Boy 1 & 2
Game Genie (older versions require the "launch system timing" option enabled in the System Menu)
sd2snes & Super EverDrive & SNES PowerPak
SNES Mouse & Hyperkin Mouse
8bitdo Retro Receiver (do not remove receiver while console is on)
Super Famicom NTT Data Controller
Tristar Super 8, Super Retro Advance, Retro-bit RetroGen
Super UFO Pro 8
Nakitek SNES Game Saver Plus
Bung SF II Professor, Game Doctor SF2-7 and other floppy drive based copiers (floppy drives should be powered separately)
Pro Action Replay

Confirmed Non-Working Peripherals

Nintendo Super Scope, Konami Justifier and the Multi-Purpose Arcade Combat Simulator (M.A.C.S.)
These light guns only work with a 15KHz (standard definition) CRT.  The last one was only made for use by the U.S. Military and is extremely rare.  Light gun games will run just fine on the Super Nt, but you cannot play them because the

Broadcast Satellaview & Exertainment Life Cycle Fitness Bike
These devices require a SNES with an expansion port on the bottom. The sd2snes is the best way you can play some Satellaview games on hardware.  The Life Cycle Fitness Bike, the adapter that plugs into the expansion port and the controllers that snap onto the bicycle's handles are extremely rare.  The two games for the Fitness Bike (Mountain Bike Rally, Mountain Bike Rally/Speed Racer) have versions (Cannondale Cup, Speed Racer) that only require a standard controller.

Games with Issues/Not Working

See here for a list of the current bugs (most of which have already been fixed) :

In short, only a few games are known have issues out of nearly 2,200 games and variants.  Many people, myself included, have helped kevtris by pointing out bugs and running tests.

Games with Unfixable Issues :

Earthworm Jim 2 PAL (requires Single or Full Buffer mode for audio to sound correct, game requires perfect timing with the PAL version)
Magical Drop (can crash on real hardware in the endless or marathon modes)
Rendering Ranger R2/Targa (can crash on real hardware)
Soul Blazer (stuttering in music during opening scroll, can happen on real hardware but never happens with the European version)

Price & Shipping

Overall, the cost of owning an Analogue product has decreased.  The original Analogue Nt was $499.00 for the RGB version and $579.00 ($549.00 for early orders) for the HDMI version.  The Nt Mini went for $449.00.  If you wanted a color for either device other than the standard silver, that cost you an additional $50.  The Super Nt costs $189.99 for any of the four color choices.

The price of the Super Nt had a huge impact on sales.  I estimate that the original Nt sold about 2,000 units and the Nt Mini about 2,500.  I was far from the first to buy an Nt Mini or a Super Nt, and my order number for the Super Nt was nearly double the order number of the Nt Mini.  Judging from my order numbers, I would estimate that Analogue has sold 5,000 Super Nt after the first batch sold out in late January.

The shipping cost something of a pill.  My Nt Mini and Super Nt cost about $37.00 to ship from Seattle or Las Vegas to the East Coast.  However, you are told what the shipping cost will be before you confirm your order, so if you find the cost too high, you are not obligated to pay it.

As I am writing this, I have had my system for just over 48 hours.  Analogue shipped it on February 6 and I received it on February 8.  Ironically, I did not receive a status update email from Analogue until February 9.  However, when I clicked on the "Check Status" in my order confirmation email on February 7, I was able to see that my package had been shipped and the expected delivery date.  Maybe I got mine sooner because Analogue used USPS to ship to a P.O. Box, I cannot be sure.  There are many people still anxiously awaiting theirs, even though they paid for their units on the first date they were available for pre-order.

It is unfair that the first to pay will not be the first to play, but Analogue explained they had some trouble with their shipping processor.  The Super Nt is a huge increase in the volume of orders they had to process and there are undoubtedly bound to be issues with a new processor.  Even the mighty Amazon sometimes screws up on occasion, and they are a company with a market cap in the tens or hundreds of billions.  Analogue is a boutique supplier of retro video game products.

Higan and Emulation

People have asked "Why pay $189.99 + shipping" when Higan runs all these games for free?"  Byuu, the author of Higan, seemed very upset with Analogue's Chris Taber for comments lumping emulators as second-rate retro experiences.  When it comes to ZSNES or SNES9X, those emulators were never particularly focused on accuracy and by today's standards are second-rate.  There are many second-rate system cores in the MiST FPGA device.  An FPGA must be instructed how to function with a hardware description language like VHDL or Verilog, and the closer the programmer can get to the true functionality of the device to be simulated, the more accurate the FPGA implementation of that device will become.

Byuu's emulator has focused on 100% compatibility and his own achievement in doing that and SNES game preservation (remember that almost tragic tale of 500 SNES PAL carts shipped to him that the postal service nearly lost but ultimately recovered) should not have been denigrated, even indirectly.  Kevtris specifically acknowledge byuu in the Special Thanks section of the Super Nt menu and has found the bsnes+ debugger instrumental in exploring the problems presented by some of these games above.  Higan does not have any of the game issues identified above except for the shield issue in Mega Lo Mania.

Emulators can perform certain functions far more easily than an FPGA.  Want to add cheat codes?  Easy.  Have that special CRT-shader scaler you like?  No problem.  Instant ROM loading?  Got you covered.  Save states?  Cheat to your heart's content.  Overclocking?  Go for it.  Light gun simulation via mouse?  Fire away!  4K scaling?  If you have the horsepower!  With an FPGA these features require serious logic resources and some features like 4K scaling are simply not possible today with consumer-affordable FPGAs.

But back to the question, why not just use Higan and be done with hardware?  Higan has two issues.  The first is latency, which in a PC comes from three sources : input protocols such as USB, operating system resource allocation, emulator input processing and output rendering.  The Super Nt bypasses all three of those sources of lag.  The only source of lag it must deal with is the display, something that Higan too must deal with.

The second Higan issue is its performance requirements.  Simply put, current Higan is focused strictly on accuracy and to get the video and audio in perfect synchronization in the accuracy version requires a tremendous amount of CPU power.  My Core i7 4770K PC cannot handle some of the special chip games at full speed.  Upgrading to a machine fast enough to run any SNES game at full speed in Higan and with minimal latency is likely to be extraordinarily expensive.  The price of the Super Nt seems much more reasonable to my wallet.

Still, getting a good SNES hardware experience is NOT cheap.  Look at the cartridges I have placed in the first picture.  The Super Nt costs $189.99, the sd2snes is $197.00, SMB RPG is about $60, Yoshi's Island is about $40, Star Fox is about $15, KDL3 is about $110 and KSS goes for about $45 and on a good day you can score a SGB2 for about $65.  An original controller in decent shape goes for $15.

Modding your SNES

Another objection to devices like the Super Nt is why not just use original hardware?  Original hardware has the benefit of removing unknown compatibility issues.  But the original SNES has some video issues.  The earlier consoles use a separate CPU and a pair of PPU chips and they have rather fuzzy video quality.  Later consoles combine these three chips into a single large chip (the 1chip but have a few compatibility issues.  The SNES mini/jr. also has a 1chip but no S-Video or RGB output without a mod.

There were two revisions of the SNES CPU, one revision of SNES PPU1 and three revisions of SNES PPU2.  Consoles may contain a CPU/PPU1/PPU2 combination of a 1/1/1, a 2/1/1, a 2/1/2 and a 2/1/3.  Kevtris aimed to recreate the behavior of the 2/1/3 consoles because they are by far the most common.  1Chip consoles also contain a 2/1/3, but whatever changes Nintendo made to get them into a single IC package caused compatibility issues.

There are three good solutions for outputting the SNES to a modern TV.  The cheapest is the HD Retrovision Component video cable.  This cable converts RGB to component video, which more flat screen TVs support.  But the TV must accept a 240p signal over component and the quality will largely dependent on your TV's scaling.  The next option is the Open Source Scan Converter, which will upscale 240p RGB or Component to HDMI in 480p, 720p & 1080p and even 1200p.  It does not add appreciable lag but it will not convert the frame rate.  Many displays will not like the 60.0988fps of the NES or SNES and won't display those systems.  The final and most expensive option is the X-RGB Mini Framemeister.  This unit does a great job of upscaling 240p content to 1080p and converts the frame rate to ensure compatibility with all displays.  It does add about one frame of latency.

The SNES processes all video and audio digitally until it sends them through (internal video, external audio) DACs.  The Super Nt eliminates the analog stage and the quality drops from converting from digital to analog.  Unlike the NES or the N64, there is no way to directly tap digital video output for an HDMI mod with the original SNES hardware.  The Super Nt is designed with both quality and compatibility in mind.  The average tech-savvy consumer should be able to get it displaying according to their preferences after only a few minutes of tweaking settings.


I find it difficult to express how much I really like the little Super Nt.  The price, the features (video especially), the near 100% compatibility at launch, the lack of latency.  Of course there are two unanswered questions about the system.  The first is an analog adapter DAC Analogue announced for the system.  The idea is that it would send a "raw" signal to the box which would convert it into high-quality RGB, Component, S-Video and Composite output.  If that came to fruition at a reasonable price and 1-chip levels of video sharpness, then I would suspect that many RGB purists would seriously consider buying the Super Nt.  Speedrunners would be able to enjoy the true SNES framerate without any latency or screen tearing.

The second open question is whether there will be jailbreak firmware for the Super Nt as there was for the Nt Mini.  People are hoping kevtris will release firmware that will allow the Super Nt to load ROMs from the SD card slot, run SNES special chip games and port his Nt Mini cores to the Super Nt and implement 16-bit cores for the Turbo Grafx and Sega Genesis.  Well, the last one is almost definitely out, kevtris has stated publicly that he has never touched an FPGA implementation of the Genesis or the Turbo Grafx 16.  Regarding other jailbreaks, speculation has been rampant but Analogue and kevtris have kept their cards close to their vests.  Neither has made a statement confirming or denying the release of a jailbreak firmware.

If anything, we are likely to see the first, that is very similar to what the Super Nt does when it loads the Turrican games.  We may see some special chip emulation at some point, but the Super FX and SA-1 chips are very complex, but we are highly unlikely to see an MSU1 implementation.  Porting over the Nt Mini cores would be doable for the most part, but just remember that the Nt Mini had Famicom features (expansion port, microphone input, slot for the FDS) and NES features (four-player adapter) that the Super Nt lacks.  The cores that require a keyboard would require a different way to implement a keyboard adapter for the the Super Nt's ports.


  1. Another great write-up. Thanks for putting so much time and attention in your posts. I'm always coming back to them as references.

  2. I can confirm that the Pro Action Replay works. Just loaded up a infinite lives code in Super Mario World and it worked just fine.

  3. There's a major graphics glitch with the first boss from the NTSC-U version of Power Rangers running off the SD Card with the jailbreak firmware.

  4. I'm having trouble with Equinox. Whenever I pick up an apple it freezes but music still plays. If I play on an original SNES it won't crash though. I am also using a Super Everdrive. If you could test it out for me I would be very grateful, I sent an E-mail to analogue and hopefully they fix it in the next update, obviously it's the Super NT and not the everdrive. I tried multiple roms of it as well.

  5. I could not find any issue with either Power Rangers fighting game.

    Equinox on the Super EverDrive and the Super Nt has a weird issue. kevtris has the DSP version of the Super ED and found that the game will work if you turn the DSP on. The weirdness is that a real Equinox cartridge does not have a DSP chip in it. The reason for this is because Equinox reads an memory area which is open bus, but the Super ED's bus capacitance settings in the non-DSP mode prevents open bus from behaving as it should. This may be fixable in a Super ED firmware update, because when the DSP is turned on the bus capacitance is changed so open bus reads will return the value the game expects.