I got to do some game testing on my firmware 4.55 PS4 last night. I acquired a couple PKG files to test with and used my ESP8266 to enabled HEN. I copied over the PKG files to a ExFAT formatted USB drive and plugged it into the PS4. I then went to Settings>Debug Settings>Game>Package Installer and installed all packages.
Excuse the crappy photo of the TV
I am now FINALLY able to play PT. All the packages I installed worked without issues except Burnout Paradise Remastered since its needs firmware 5.05 to run.
Side note: I own all the retail games I installed/tested from PKG’s, just thought I should add that. PT is only a demo obviously.