PSPPack is a PlayStation Portable executable packer / encrypter that can be used to create very small files
(like 4k or bigger intros / homebrews) compatible with PSP official firmware.
It generates prxs based eboots, doesn't rely on pre-forged commercial games headers like other packers and is made to produce the smallest possible eboot from a given prx.
I used it on these prods (so far):
https://www.pouet.net/prod.php?which=91972
https://www.pouet.net/prod.php?which=91981
https://www.pouet.net/prod.php?which=92090