Install Free McBoot on a memory card (using a friend’s modded PS2 or buying pre-made cards on eBay). Then run to load the Code Breaker ISO from:

As I don't want to provide any direct links to potentially pirated content, I recommend searching for the file on Romhacking.net or EmuCR.

and other classic consoles. While it was originally sold as a physical disc, it is now widely used in for modern setups, including emulators and modified hardware. Overview of Version 7.0

: Copy the ISO to your DVD folder. Note that Code Breaker often requires specific "Compatibility Modes" to be enabled in OPL settings.