: Once you have a folder, use PS3 ISO Tools to convert that folder into a final .iso image. Method 3: Creating macOS Bootable ISOs
Use a "PS3 DISC.SFB generator" to create this tiny file. It tells the console what the Game ID is.
Thus:
Once you have a valid game folder, you can build the ISO image. PS3 ISO Tools (version 2.2 is standard).