ModuleNotFoundError: No module named 'serial'

This error occurs when your Python environment lacks the 'pyserial' library, which provides the 'serial' module. This is extremely common when running hardware-adjacent scripts like bootloader unlockers (e.g., Echo Spot 'rook'), kernel debuggers, or Arduino serial monitors.

• The 'pyserial' library is not installed in your current interpreter context
• Mismatched package name: You may have tried 'pip install serial' (incorrect) instead of 'pip install pyserial'
• Missing system-wide dependencies on Fedora or Ubuntu if running scripts with 'sudo'