Running pirated games on PS2 has always been possible, but it has never been within everyone’s reach.
With FreeMcBoot you can take advantage of a bug in the memory card management (fixed in the last slim PS2 production batch) to load games from USB or on hard disk (on PS2 “fat” first version). But you have to have a memory card created in a special way and at the time it was not easy. (At least: you paid a lot of money for the installation “service”)Or with swap disks or action replay, but even so it’s not as easy as putting a disk in the drive.
Then there is modification via modchip. The chip alone costs very little (5 euro) but soldering 20 solder on the tiny pads of the motherboard is absolutely not within everyone’s reach. And so, a 5 euro chip with 100 euro of labor…
But now there is FreeDVDBoot: CTurt has found a way to run burned games without modification.
Creating a video DVD in a special way, you can insert an exploit in the DVD menu that allows foreign code to be executed.
So, the PS2 starts playing the DVD video (which works with homemade discs), then the menu contains “malicious” code that runs something else, homebrew, emulators, or even a commercial game.
Like the exploit used 20 years ago on the Sega Dreamcast: the copied game pretended to be a MIL-CD (music format used only in Japan and only used by 4-5 albums in total), then played the full game.
There are currently no tools released to make the operation easy: the game must be set in a specific way with a special launcher, it doesn’t work with just any copy. For the launcher there is no source code but only the explanation of the operation: the programmer (who if I understand correctly works for Microsoft) doesn’t want to have anything to do with piracy and would like his work to be used only for homebrew.
I’m sure there will be someone else who will complete the work: ESR (the program used to load the burned games “disguised” as DVD movies) was published over 10 years ago, the only difference is that it was necessary to load it via FreeMcBoot (the “special” memory card), now you can load it more easily.