PCB reverse engineering (also called PCB cloning or PCB copy) extracts design information from an existing board to recreate or modify it.

What It Involves:
1. PCB Cloning: Scanning layers, tracing copper connections, reproducing schematic and Gerber files.
2. IC Chip Decryption: Reading read-protected microcontroller firmware.
3. Decapsulation: Opening chip packages to expose the silicon die.

How PCB Cloning Works:
- High-resolution microscopy scans each copper layer.
- Trace nets, vias, and pad locations layer by layer.
- Reconstruct the schematic from the netlist.
- Generate new Gerber files for fabrication.

IC Chip Decryption:
- MCUs (STM8, STM32, PIC, AVR) have readout protection.
- Methods: fault injection, voltage manipulation, optical decapsulation.
- Firmware can then be re-flashed onto new chips.

Common Uses:
- Repairing legacy equipment when original files are lost.
- Recovering design files when the designer is unavailable.
- Understanding competitors for interoperability.
- Production backup and redundancy.

Note: Reverse engineering should only be done on boards you own or have legal rights to. Respect intellectual property.