PSP Filer Go working on OFW.
It's just a signed loader that loads static homebrew.PSPFiler 6.6 for PSP Go - signed.zip
You can try it out with other static homebrew too, but I don't guarantee that it'll work for every homebrew.
Just unpack the EBOOT.PBP from the file above, unpack another homebrew EBOOT.PBP, then name it's DATA.PSP to DATA.PSAR, then pack it with the DATA.PSP from the file above.
It'll only work for static homebrew, relocatable homebrew already work with the normal way of signing.
The DATA.PSP that you pack from another homebrew must NOT be signed, leave it decrypted.