Did the Sinclair ZX Spectrum+ Have a ROM Easter Egg?

This article investigates the long-standing rumor regarding a hidden Easter egg within the Sinclair ZX Spectrum+ read-only memory. We will examine the technical specifications of the Issue 4 ROM, analyze popular urban legends involving specific POKE commands, and reveal the truth about developer signatures hidden within the code.

The Sinclair ZX Spectrum+ was released in 1984 as an updated version of the original ZX Spectrum 48K. While it featured a new keyboard with hard plastic keys and a reset button, the internal architecture remained largely identical to its predecessor. Specifically, the Spectrum+ utilized the Issue 4 ROM, which handled the BASIC interpreter and the operating system. Because the hardware and software were so closely tied to the original model, any secrets hidden in the original ROM were carried over to the Plus model, fueling decades of speculation among retro computing enthusiasts.

For years, a persistent myth circulated through magazines and playgrounds claiming that a specific command could reveal a hidden message or game. The most common legend involved typing PRINT USR 65368 or executing a series of POKE commands to alter memory addresses. Users claimed these inputs would display a secret message from the developers or unlock a hidden graphics mode. In reality, executing these commands on a standard Spectrum+ usually results in a system crash or an error message, as the memory addresses referenced do not contain executable subroutines designed for public interaction.

Despite the lack of a functional Easter egg, there are indeed hidden strings within the ROM code. Disassembly of the Issue 4 ROM reveals copyright information and the names of the key developers responsible for the machine’s creation. Steve Vickers, who wrote the BASIC interpreter, and John Grant, who worked on the floating point arithmetic, left their marks within the hexadecimal code. While these are not playful secrets in the modern sense of an Easter egg, they serve as a digital signature from the engineers who built the iconic computer.

Ultimately, the Sinclair ZX Spectrum+ does not contain a traditional hidden Easter egg like those found in later 128K models or modern software. The startup screen displays the standard copyright notice, and no combination of keys reveals a hidden game or menu. The legend persists as a testament to the curiosity of the user base, but the only true secrets buried in the ROM are the names of the creators themselves, hidden in plain sight within the machine code.