firmware

/ˈfɜrmˌwɛr/
noun
  1. Software that is permanently stored in a hardware device (such as a computer, router, or smartphone) and controls how it operates.
    • The printer's firmware controls how it communicates with your computer.
    • Some devices allow you to install custom firmware to add new features.
    • You need to update the firmware on your router to fix the security issue.