Gave this a go, not sure if I know what I'm doing.
Couple questions though.
Is the act.dat essential? I couldn't seem to find it in my extdata folder.
How can we tell if the EBOOT has been decrypted successfully,
Will Cygwin output a .elf/.self without it being decrypted properly?
(I ask because I've seen it output one while giving errors & also at another time claim an outputted .self is not a self)