The PS3’s security was fully compromised over a decade ago. Consoles with or HEN (Homebrew Enabler) can install unsigned PKG files. There are online archives and forums where users have uploaded the DLC PKG files for almost every song ever released for Rocksmith 2014.
To install non-PSN authorized packages, your PS3 needs to run either Custom Firmware (CFW) or PS3HEN (Homebrew Enabler). These modifications unlock the console's operating system, adding a "Package Manager" option to your XMB menu that allows the installation of files directly from a FAT32-formatted USB drive. 2. The RAP File Barrier rocksmith 2014 ps3 dlc pkg free