LeopardAssist can help in the process of installing OS X 10.5 Leopard on machines that did not meet the minimum system requirement of an 867MHz or faster processor. It achieves this by temporarily writing a script into the NVRAM of your G4-based Mac. Executed at startup, this script will temporarily force the system to report that a faster processor is installed, allowing the Leopard installer to successfully complete its minimum system requirements check.

This allows Leopard to be installed from unmodified installation media or another bootable device. LeopardAssist handles the interaction with Open Firmware, specifying the target processor speed, the number of physical processors in the system, the desired boot device and any additional startup flags to simplify the installation and configuration process.