Easter eggs in electronics: hidden features and industry anecdotes

While these surprises often reflect the personality and sense of humour of engineers and developers, they also offer a fascinating glimpse into the culture of electronics design and software engineering over the decades.

The origins of the electronic Easter egg

The concept of the Easter egg in electronics can be traced back to 1980 with the Atari 2600 video game Adventure. Discontent with the lack of developer credit, programmer Warren Robinett secretly included a hidden room containing a message identifying himself as the game’s creator. At a time when corporate policies prohibited the public naming of developers, this act of defiance not only made history but also established a long-standing tradition within the industry.

Since then, Easter eggs have appeared in various guises, from hidden test modes in consumer electronics to concealed developer menus in embedded systems.

Easter eggs in hardware and firmware

While software Easter eggs are widely known, hardware design has its own history of concealed features and quirks:

• Oscilloscope hidden modes: some digital oscilloscopes and logic analysers feature undocumented test screens or performance metrics, activated through specific button combinations. These are typically intended for factory diagnostics but are occasionally left accessible in production units
• Silicon etching signatures: semiconductor designers have been known to etch tiny cartoons, initials, or messages into the photomasks of chips. These are invisible during normal operation but can be revealed under a microscope during failure analysis or academic teardown
• Hidden debug interfaces: certain embedded systems leave inactive or undocumented serial interfaces or JTAG connectors on their boards, sometimes deliberately for service engineers, but occasionally accessible to hobbyists and reverse engineers

Software Easter eggs in electronics tools

Development tools and electronic design software are equally prone to Easter eggs:

• EDA software secrets: several PCB layout tools and simulation packages have included Easter eggs over the years. For instance, users of earlier versions of certain packages might recall hidden animations, developer credits, or jokes accessed through obscure command sequences
• Calculator quirks: some early programmable scientific calculators contained undocumented functions or sequences that revealed additional operations, test modes, or personal messages from the development team

Industry anecdotes and notable examples

One of the most famous anecdotes comes from early IBM PC BIOS firmware, where developers embedded obscure diagnostic routines activated via specific hardware jumper settings. While officially undocumented, these features became known within engineering circles and were occasionally referenced in third-party service manuals.

In another example, an automotive infotainment system reportedly contained a hidden screen displaying the software team’s group photo, accessible through an intricate button sequence – an Easter egg subsequently removed in later software updates due to corporate policy changes.

The decline of the engineering Easter egg

In recent years, the practice of including Easter eggs in commercial electronics has declined. As devices have grown more interconnected and subject to stringent cybersecurity standards, undocumented features – even harmless ones – are increasingly viewed as potential vulnerabilities. Regulatory frameworks such as ISO 26262 in automotive electronics and IEC 62304 in medical device software explicitly discourage undocumented behaviour in safety-critical systems.

Nevertheless, the tradition endures within hobbyist communities, open-source projects, and test utilities, maintaining a link to the personal, human side of electronics engineering.