Modchips

The modchips used on the PlayStation 1 (PS1) are a variety of devices designed to bypass the console’s built-in media authentication system. It's important to clarify that this mechanism isn't exactly "copy protection" in the conventional sense. Instead of checking the content of the disc itself, the PS1's security system is focused on identifying whether the media has a unique "fingerprint" that matches a licensed disc. Essentially, the system performs a check to determine if the disc is an official, authorized product. This is why methods like the "swap trick" were so effective — as long as a legitimate, licensed game disc was present when the console performed its initial media check, it could later be swapped for a backup or copy, and the console would continue to boot the new disc without issue.

The reason for this is that the console wasn't verifying the data written on the disc but instead looking for specific characteristics tied to the official discs produced by Sony. Once the licensed disc was detected during the boot process, the PS1 would allow the swap to occur. However, later revisions of the PS1 introduced more advanced boot ROMs, which included an additional media verification step, making the process more complex. As a result, these updated consoles required a "double swap" — the player would need to perform two disc swaps to bypass both checks, further complicating the procedure.

This incremental change in the PS1's security reflects the console manufacturer's attempt to counteract these workarounds, but modchips, along with swap tricks, remained effective tools for circumventing these measures throughout the lifespan of the console.

Early Modchips

1. Old Crow

In 1997 a new modchip was released called “Old Crow”. This new modchip was another clone of the original modchip, but the source code was released to the public, reducing the cost of the chip even further. “Old Crow” was originally made for the Zilog Z8 microcontroller, but versions were released for the PIC16C54, and PIC16C84 as well.

Later in 1997 the “Old Crow” code was ported to the then new PIC12C508 microcontroller, which is still being used for modchips today. The new chip dropped the modchip prices to the price range they are still sold at today.