Jotego Restores Missing Pixels in Latest CPS Core Update

FPGA developer Jotego has released a targeted fix for the JTCPS arcade cores that corrects a visual error where the top line of object pixels was failing to render. The update, which was detailed in a commit to the project's GitHub repository on January 25, 2026, specifically addresses issue #1283 regarding sprite rendering accuracy.

For the casual observer, a single missing line of pixels might seem like a trivial grievance. It is the sort of detail that would likely go unnoticed on a blurry CRT in a smoky arcade back in 1992. However, the MiSTer FPGA community does not operate on "good enough" logic. The goal is hardware-level replication, and if the original board drew that top line of pixels, the core needs to draw it too.

The Pursuit of the Perfect Sprite

The fix applies to the JTCPS ecosystem, which handles the emulation of Capcom's legendary arcade hardware. This includes the CPS1, CPS1.5, and CPS2 systems. These are the boards that powered the golden age of the arcade fighting game boom, hosting titles like Street Fighter II, Final Fight, and Strider.

According to the commit notes, the update "fixes missing top line of objects." In the context of arcade hardware, "objects" usually refers to sprites—the moving characters, projectiles, and items that populate the game world. A missing top line could result in subtle visual oddities, such as flattened heads on characters or slightly truncated UI elements. While it likely didn't break gameplay logic, it represented a deviation from the original hardware's behavior.

This kind of granular maintenance is typical for Jotego (Jose Tejada), whose work has become a cornerstone of the open-source FPGA gaming scene. While many cores are developed by loose collectives, Jotego operates with a more structured approach, often tackling the most difficult chips that require decapping and die analysis to understand fully.

Why Accuracy Matters

The Capcom Play System hardware is notoriously complex. The CPS2, for instance, employed sophisticated encryption that kept emulators at bay for years. When Jotego began working on these cores for the MiSTer project, the objective was to move beyond software emulation quirks and replicate the logic gates of the original chips.

In software emulation, a missing line of pixels might be patched over with a graphical hack. In FPGA development, a glitch like this usually indicates a misunderstanding of how the video processor fetches or draws data. Fixing the "missing top line" isn't just about making Ryu look slightly better. It is about correcting the timing and logic of the video signal itself.

This update is particularly relevant for enthusiasts who use the MiSTer inside original arcade cabinets. When displayed on a large, high-quality RGB monitor, even minor rendering errors become glaringly obvious. A sprite that is one pixel too short can look jarring against a pixel-perfect background.

Updating Your Setup

The fix has been pushed to the main repository. Users utilizing standard update scripts, such as the popular update_all script for MiSTer, should receive the corrected core files during their next run. It is worth checking your settings to ensure you are pulling from the correct beta or public branches depending on your support tier for Jotego's work.

While this update won't drastically change the way Captain Commando plays, it brings the simulation one step closer to the original printed circuit boards. And for a community that spends hundreds of dollars on scalers and CRTs to recreate the year 1993, that single line of pixels is worth the effort.