PlayStation 2 can play homebrew games by using DVD player exploits
You don't need to mod the hardware at all.
The PlayStation 2 is over 20 years old, but it’s still difficult to hack if you want to run homebrew games without tweaking the hardware. You usually need to install a modchip, buy a specially-configured memory card or even pry the system open to block the disc reader’s sensors. However, it might just be a matter of using the discs themselves to fool the console. Security software engineer CTurt has developed a homebrew app method that exploits the DVD player function to run unofficial code. The approach involves corrupting key functions in the files DVD movies always contain, and then loading a second, more advanced stage that isn’t constrained like the first.
The technique is still young, but already works reasonably well. You just need to put a disc in the PS2’s drive and wait for it to load. You can even boot into a menu to choose from multiple games stored on a single disc. It also hints at opportunities to allow unofficial games on other systems — CTurt believes this could work for other PlayStation models. That might not be an option for long when some PS5 models won’t include disc drives, but it does raise hope for those wanting to expand their game collections with unofficial titles.
