Reverse engineering in electronics

What is reverse engineering?

Reverse engineering, also referred to as back engineering, is the process of thoroughly analyzing a finished product or system to understand how it was designed and how exactly it works. In the context of electronics, this involves examining electronic devices, from simple circuits to complex systems, to recreate their schematics, operating principles, and construction methods. Reverse engineering allows for discovering how a circuit was built, what components it consists of, and what design solutions were applied, even in the absence of manufacturer documentation. The reasons for using reverse engineering vary. Often, it is used to obtain the necessary information to construct a device with similar functionality or to ensure compatibility with an existing product.

Reverse-engineering process

To reverse-engineer a completed electronic design, engineers must follow a series of steps and utilize a variety of methods and tools. In electronics, the reverse-engineering process typically involves both physical (hardware) examination and software (firmware) analysis. The key elements of this process are described below.

• Disassembly and inspection of the device. The first step is to disassemble the device, meaning physically taking it apart. In practice, this involves carefully opening the case and removing all printed circuit boards (PCBs), modules, and components. It is common for simply taking apart and visually inspecting the product to provide valuable information. For example, it allows for reading the markings on integrated circuits or assessing the quality of soldering and assembly. Engineers document each component. A thorough visual inspection of the assembly provides a basis for further analysis, helping to identify which circuit sections correspond to specific functions (e.g., power, control, communication) and what types of components are present in them.
• Schematic creation and circuit analysis. The next important step is to analyze the printed circuit board and reconstruct the electrical schematic of the device. With the PCB exposed, the engineer identifies the connections between components, or paths on the laminate, to understand the circuit architecture. In the past, this required visually tracing the paths with the naked eye or using a magnifying glass, layer by layer. Today, this process is largely automated. With multilayer circuits, the board can be successively sanded, and each layer scanned, in order to reconstruct a complete network of connections (netlist) by computer. Based on the collected data, a schematic diagram of the device is created, showing which elements are connected to each other and how. In addition to the schematic itself, it is important to compile a component list (BOM), including the values of components (resistances, capacitances, etc.) and information about their types and manufacturers. In practice, engineers document the designations of integrated circuits, transistors, diodes, etc., from their cases to retrieve their documentation (catalog notes) later. However, this is often not easy, as many components, such as capacitors or custom ICs, may lack clear markings on their surface. In such situations, specialists must resort to additional techniques.
• Integrated circuit analysis. When the equipment being analyzed contains integrated circuits (microprocessors, FPGAs, specialized chips, etc.), there is often a need to examine these components more closely. If we encounter a chip with an obfuscated or unknown designation when compiling the component list, we can try to identify it by analyzing its internal structure. To do this, laboratory techniques are used, such as decapsulation (decapping), which is the removal of the IC case. This is most often done by etching the plastic casing with the appropriate acid until the silicon wafer of the chip is exposed. The semiconductor structure is then viewed under a microscope. Sometimes the chip manufacturer leaves a small symbol or series marking on the silicon die, which makes it possible to identify the component. For reverse engineering, such information is valuable when trying to reproduce the operation of a circuit or looking for a replacement. Based on the analysis, it’s sometimes possible to select another component with similar functionality if the original is unknown or unavailable.It should be emphasized that microscopic methods are usually a last resort and are mainly used when analyzing highly complex or protected devices. In most typical cases of reverse engineering in electronics, a thorough analysis of the schematic and function of integrated circuits based on their catalog documentation is sufficient.
• Firmware reading and software analysis. Modern electronics is not only about hardware but also about embedded software, known as firmware. Firmware is the program stored in a device’s memory (such as a microcontroller) that controls its operation. Complete reverse engineering of an electronic device therefore also includes reading and analyzing the firmware. Engineers first attempt to extract the device’s raw binary code. This can be done through service or debug connectors (such as JTAG or SWD), direct memory access from flash memory chips, or using official firmware updates if available. Once the binary code has been obtained, the next step is to disassemble it into low-level machine instructions that can be analyzed by engineers. With the help of specialized tools (disassemblers and decompilers), experts can analyze the execution flow of instructions within the device and, based on this, understand its algorithms. Firmware analysis can be challenging because manufacturers often secure their software, for example, by encrypting it or blocking memory access. Reverse engineering of code is also crucial for security analysis, allowing testers to identify vulnerabilities in the device’s software. Through disassembly, it is possible to detect code fragments responsible for security features (e.g., mechanisms that verify licenses, passwords, or encryption of communications) and determine if they can be bypassed or strengthened. In this way, software reverse engineering contributes to enhancing system security and optimizing performance. A comprehensive reproduction of complex electronic systems often requires combining the results of both hardware and software analysis.

Reverse engineering applications

Repair, optimization, and upgrade of equipment

One of the primary applications of reverse engineering is the repair and maintenance of older equipment. When a manufacturer fails to provide technical documentation or has discontinued support for a particular model, recreating the schematics and operating principles of the device is sometimes the only way to successfully repair it.Through reverse analysis, faulty components or design flaws can be identified, and solutions can be found to fix or circumvent them. Reverse engineering can extend the life of equipment that would otherwise be discarded.By measuring and digitally recreating such missing components, it is possible to manufacture new, compatible parts and restore the device to full working condition.

Besides repairs, reverse engineering is also widely used to optimize and modernize existing electronic systems. If we have a device with known functionality, we may want to improve it for example, by increasing its speed, reducing power consumption, adding new features, or upgrading obsolete components. Reverse analysis provides a complete set of documentation (schematics, parts lists, software logic), which serves as a basis for engineers to propose improvements. For example, a manufacturer may reconstruct the schematic of an old module and replace discontinued components with new ones offering better parameters. Alternatively, engineers can analyze firmware code to find fragments that slow down operation and reprogram them. Such an approach is also useful when expanding the device with new functions. If we have an accurate model of its operation (both hardware and software), it is easier to design an additional module or extension that will work properly with the system. Reverse engineering thus makes it possible to modernize a product without the need for designing it from scratch.

Analysis of competing products

Another important application of reverse engineering is the analysis of competitors’ products. In the electronics industry, companies regularly buy and disassemble devices from other manufacturers to find out how they were built. This allows them to thoroughly analyze how the competition works and then use this data to improve their own products. Thanks to this, it is possible to discover what innovative solutions were used by competitors, how they assembled the device, what components they used, which integrated circuits they applied, and how they solved specific technical problems. Information obtained this way is extremely valuable for business, as it is usually not publicly available (companies protect the details of their designs as trade secrets). The results of reverse engineering a competitor’s product can be used in many ways. First, engineers can assess what worked well in a given device and what can be improved. This, in turn, inspires the design of an improved version of one’s own electronic device. Secondly, reverse engineering makes it possible to estimate the production costs of a competing product. Based on the identified components and manufacturing technology, it is possible to approximately determine how much it costs to produce a given device (a practice known as “reverse costing,” i.e., analyzing the cost of a product based on its disassembly). This information helps a company optimize its own designs from an economic perspective, for example, by indicating which components could be replaced with cheaper equivalents without compromising quality. Finally, analyzing competitors’ devices is often essential to ensure compatibility. If we want our equipment to work with products from another company (e.g., use the same interface or accessories), we often need to replicate the communication protocol or the way a connector operates, which requires reverse engineering of the original device.

Security and equipment testing

Reverse engineering plays an important role in the security of electronic devices and in testing their resistance to attacks and failures. Security specialists (known as white-hat hackers or security engineers) use reverse engineering methods to analyze other people’s devices and systems in search of vulnerabilities. By analyzing firmware code, hardware architecture, and the encryption algorithms used, they can detect security gaps, weaknesses, or hidden malicious functions. Reverse engineering makes it possible, for example, to discover that a device is transmitting unencrypted sensitive data or that it has a backdoor left by the manufacturer. Such information helps mitigate threats and secure the system against potential attacks. The R&D departments of many electronics companies conduct internal security audits of their products precisely by deliberately disassembling them into their fundamental components.

Reverse engineering is also used for general testing and verification of equipment. By carefully analyzing the design of a device, it is possible to assess whether it meets the required standards and norms (e.g., those related to EMC). If a product has undergone reverse engineering and no major design flaws have been found, it is more likely that the device has been well-designed and will be reliable. In this way, manufacturers can independently verify the quality of products (both their own and those supplied by subcontractors). To summarize, the use of reverse engineering in the field of security and testing provides a dual benefit: on one hand, it enhances the device’s resistance to threats, and on the other, it verifies its structural integrity.

What are the advantages and disadvantages of using reverse engineering?

Benefits of reverse engineering

• Identifying defects and improving reliability. A thorough analysis of a design allows for the detection of hidden flaws or weak points in a project. Thanks to reverse engineering, the causes of device failures can be understood and eliminated in subsequent versions. As a result, devices become more refined and resistant to errors.
• Enhancing performance and functionality. Gaining a full understanding of how a system operates provides an opportunity to improve its parameters. Reverse engineering often leads to increased efficiency and performance, for example, through software optimization or the introduction of better components. Findings from reverse analysis can be used to design an electronic device in a new version or even create an entirely new product that will be more competitive in the market. In other words, reverse engineering stimulates innovation by learning from existing solutions.
• Cost Optimization. Reverse engineering provides information not only about how a device works but also about what it was built from and for how much. By analyzing a disassembled product, it is possible to draw up a cost estimate for components, assembly technology, and manufacturing technology (known as reverse costing). Such knowledge translates into cost optimization in your own projects. For companies, this means the ability to reduce manufacturing costs without compromising quality, thereby increasing margins or offering customers a cheaper product.

Access to documentation and technical knowledge. It is not uncommon for the original technical documentation of a device to be unavailable (e.g., lost, unpublished, or proprietary by the manufacturer). Reverse engineering makes it possible to recreate complete documentation, including schematics, PCB layout, parts lists, and even portions of source code. Such reconstructed documentation can be invaluable to R&D and maintenance departments. It reduces the time it takes to design new solutions (because you can rely on already proven patterns) and saves resources that would have to be invested in developing everything from scratch.

Challenges and limitations

• Legal and ethical issues. Legal and ethical issues. The use of reverse engineering may encounter legal barriers. In many countries, unauthorized disassembly of someone else’s product and analysis of its operation (especially software) may violate copyright laws or intellectual property regulations. This is particularly relevant when the information obtained through this method is used to copy a solution and introduce a competing product to the market. For example, cloning a patented electronic circuit without the consent of the patent holder is illegal. Likewise, software licenses often explicitly prohibit code disassembly. As a result, reverse engineering is frequently the subject of legal controversies and disputes. When operating in this field, companies must exercise caution and ensure they remain within the boundaries of permissible use (e.g., reverse engineering for ensuring compatibility is often legally acceptable, whereas copying a product is not).
• Technical complexity and resources required. Performing full reverse engineering of an advanced device is a very complex, time-consuming, and sometimes expensive task. It requires extensive knowledge in many fields: analog and digital electronics, microtechnology, low-level programming, and even chemistry (when decapitating circuits). Specialized equipment is also required, from shop tools (soldering irons, optical microscopes) to expensive equipment like 3D scanners for PCBs and logic analyzers. It is difficult for one person to master all these skills, which is why usually a team of experts with complementary competencies works on a reverse engineering project. Even with a good staff, the process can take a long time. Disassembling and mapping a multilayered smartphone motherboard can take many weeks. In addition, there is no guarantee of complete success: manufacturers are using increasingly advanced safeguards (e.g., flooding chips with resin, encrypting firmware, unusual screws, or adhesives that make disassembly difficult), which can make it impossible to access certain information without destroying the device. In short, reverse engineering is a logistical and technical challenge that is not always cost-effective. Sometimes, it is cheaper and faster to design a new electrical device than to try to replicate an existing device down to the smallest detail.
• Risk of damage to the equipment. In the course of reverse analysis, it is easy to permanently damage the equipment under test. Disassembly can break fragile components, and board grinding destroys them irretrievably, while attempts to read memory or debug may result in erasing the contents of the chip due to a wrong action. Therefore, it is often assumed that one device will be sacrificed for the purpose of analysis (e.g., dissolving an IC case with acid is an irreversible action). If the product under test is expensive or difficult to access, this poses a significant limitation. Professionals minimize this risk by using appropriate techniques (e.g., desoldering components at controlled temperatures, backing up memory contents whenever possible, etc.), yet a certain degree of destruction is nevertheless inevitable in reverse engineering.
• The enormity of the data being acquired. Paradoxically, success in reverse engineering also raises the challenge of having to process and understand a huge amount of information. A complete schematic of a complex device can span hundreds of pages, a list of components may include thousands of items, and tens of thousands of lines of assembler code can emerge from software disassembly. Sorting this out and drawing meaningful conclusions requires patience and analytical skills. It is easy to get lost in this thicket of details, especially if the project was originally developed by a large team of engineers over a long period. Reverse engineers must therefore possess not only tools for data extraction but also software that aids in interpretation (e.g., CAD software for PCB reconstruction, code analysis software). Despite these challenges, a properly conducted process can provide clear and actionable knowledge. However, significant resources must be invested to achieve this.

Why is reverse engineering so important?

Reverse engineering is an extremely valuable tool in the world of electronics, combining the inquisitiveness of the researcher and the ingenuity of the engineer. It allows one to look inside electronic devices and understand their secrets—starting from circuit board connections, through the structure of integrated circuits, to the functionality encoded in firmware. This enables the extension of device lifespan, the creation of cheaper and better equivalents of existing products, and the improvement of the safety and quality of new designs. Nowadays, when technological progress is very fast, the ability to quickly analyze and understand a solution gives companies a competitive advantage and saves time required for R&D work. Looking ahead, the role of reverse engineering in electronics will likely continue to grow. More and more devices are entering the market, often without full documentation. We can also expect further development of reverse engineering tools—from advanced scanners and microscopes to intelligent software capable of automatically recognizing circuit structures or decompiling protected code through optimization techniques. At the same time, manufacturers will try to hinder unauthorized analysis of their products (e.g., through better physical and software security). There is no doubt that reverse engineering will remain a key component of technological development. It is through this process that we discover how something works, allowing us to fix, improve, or creatively adapt it. In this way, reverse engineering drives innovation and progress. If your company needs support in designing, programming, or assembling electronic devices, contact us! At Device Prototype, we offer comprehensive services from concept to finished product, tailored to your needs.