There is no official or unofficial “Guitar Hero 2” PKG file for PlayStation 4. Guitar Hero II was released exclusively for PlayStation 2 and Xbox 360 in 2006–2007. It has never been ported, remastered, or made backward compatible for the PlayStation 4 by Sony or Activision. Any file claiming to be a Guitar Hero 2 PS4 PKG is either a mislabeled homebrew project, a fake, or malicious software.
The Latency Issue: High-definition displays introduce lag that the original hardware wasn't designed for, making "official" emulation difficult. Guitar Hero 2 Ps4 Pkg
If you have a jailbroken PS4 (a console running firmware 9.00 or lower, generally), you can run emulators. The most common method is using WineHQ or RetroArch to emulate the PlayStation 2 version of the game. Report: Status of "Guitar Hero 2 PS4 PKG" 1
Guitar Hero II was never officially released for the PlayStation 4, players with a jailbroken PS4 Malware disguised as a fake installer
experience on modern hardware without the risks of unofficial PKG files, many players use: Clone Hero
: Some users have successfully injected custom tracks into existing PS4 rhythm games like Rock Band 4