This week, hackers discovered that the PlayStation 4's "remastered" version of of Parappa The Rapper is actually the 2006 PSP version of the game running on a PSP emulator. As a result, other hackers with jailbroken PS4s have been seeing how they can use Parappa The Rapper to emulate other PSP games on the home console.
Screenshot: Sony (Parappa The Rapper Remastered)
A poster who goes by the name KiiWii over at GBATemp, an emulation forum, spent the past week documenting their progress in using the emulator to run other games, including Loco Roco, which also has its own remastered version on the PS4. As Ars Technica reported, other PS4 hackers claim to have gotten a few other games, such as Patapon, running as well.
But not many games work, so far. While KiiWii reports being able to boot up Lumines, for instance, other games get stuck on the loading screen. KiiWii speculates that that may have to do with the emulator's file size limit of only 800 megabytes.
One thing the emulator does do that's new is make it possible to swap out the original textures from the UMD version of the game with higher resolution ones. That's why, despite using the same code as the PSP game, Parappa the Rapper Remastered looks really nice on PS4.
memes ( ͡° ͜ʖ ͡°) pic.twitter.com/eQKNmNkMg4
— Smug Nia :3 (@notzecoxao) May 8, 2018
Meanwhile, a PS4 hacker who goes by the name Darkelement has shared the emulator's configuration file with others adding code from other PSP homebrew projects, implying that "PSPHD", as it's now being called, will be fully operational sometime in the near future.
As Eurogamer's Digital Foundry noted, this is basically what happened when Sony started releasing PlayStation 2 Classics on the PS4 that ran via a special PS2 emulator which helped increase the resolution of the original games (as was the case with Star Ocean: Till the End of Time for instance). That emulator was also adapted by the homebrew community to run the rest of the PS2's library on hacked PS4s.