Unfortunately, after a bunch of messing around, I've determined that the ipl_bios_dumper (if it even works at all) most likely only works on an original Phat PSP using the 1.50 kernel.
Not sure if it's the same one created by moonlight.
I'm unable to do anything with it only having access to slims currently as they don't support 1.50 kernel stuff.
I'll keep a look out and attempt to pick up a phat if a store like goodwill, gamestop, craigslist, etc. has one I'm interested in.