With the OpenCore Legacy Patcher, it's possible to install macOS Sequoia on Mac computers from as far back as 2008. Here's how to get everything set up.

Attempting to install Catalina on an unsupported Mac is in no way supported by Apple, and you are doing so at your own risk. MacRumors cannot be held liable for any data loss or damage as a result.

Shut down the target Mac (the one on which you would like to install Mac OS X 10.4) Connect the target Mac to another system with a DVD drive running Mac OS X, using a standard FireWire cable.