Figure 1: The PiBoy’s firmware is essential to the operation of the handheld.
The PiBoy DMG, while being a case for a Raspberry Pi, also has a second brain. There is a microcontroller that acts a a go-between system for the handheld and the Raspberry Pi. This second chip is what the firmware controls. The firmware does several things. First, it filters and controls timing for analog controls. Secondly, it enables troubleshooting controls via the Start and Select buttons and enables a hard shutdown via the joystick in the event the Pi or the OS locks up. Lastly, it controls bringing the screen up while the Pi is booting.
The firmware may occasionally be updated by Experimental Pi and can be flashed to the PiBoy by the user. See this article for instructions on flashing your firmware.