Time to get a [ Register or Signin to view external links. ] Developers SiSTRO and [ Register or Signin to view external links. ] have released PS4 PKG2USB, a tool for the PS4 that allows owners of a hacked console to run their games from and external hard drive. The tool is compatible with both 4.05 and 4.55 consoles.

In its current state, the process to get games properly installed to an external USB drive with this tool seems pretty convoluted and error prone, but it might be useful for people who are running out of space on their internal drive. The basic idea is that you have to install the game on the internal hard drive first, then move some files from the internal disc to the external disc, update some config file at the root of the usb drive, and run pkg2usb's payload.

Additionally, some people have complained that in practice the game still needs to be on the internal hard drive, which makes the feature useless. This is a misunderstanding, probably due to the fact that the plugin does not automatically delete the original pkg file from the internal drive. Even though it's a misunderstanding, this shows the plugin is not the easiest thing to use yet.

This is great progress, and also awesome to see that this feature is also available for 4.05, but unless you are really constrained with space, I'd suggest to wait a bit, and hope that future versions of the tool will be more user friendly.

This is a PS4 payload (based on Vortex's dumper) to dump and run fake PKGs on USB.

USB drive must be formatted to exFAT
works only with fpkg (not official pkg)
game/app have to be before installed as usually on internal storage
copy ps4-pkg2usb.cfg to usb root
edit config title_id with game/app title_id
always use the same USB port that when you installed game
to reinstall game to internal hdd, remove and reinstall as usual

tip: if you still have the pkg and you want to avoid wasting time waiting for the file to be copied from the payload on the USB HDD, copy the pkg to X:\PS4\CUSAxxxxx\app.pkg