1) Turn on your PS4 7.55, go to the web browser then go to this (https://sleirsgoevy.github.io/ps4jb2/75x/). Click on "JB+MIRA" like in the picture then you need to wait for the message "Waiting for client" and "You're all set".
PS: If you have a black screen after the message just press X and the PS button on the controller to get back to the menu
PS: If you have a message "Not enough free memory" just retry or restart the console.
2) If you have this message close the web browser then go to :
3) It will show all the games in PKG that you have on the root of your hard drive. Select the one that you want to install.
4) Go to the main menu and enjoy !