Couldn't find anything on the topic, more likely than not because it wouldn't be feesable, and even if it was it wouldn't be practical (as opposed to just buying a slim).

The Homebrew software I want to run was designed around a slim running 4.xx or 5.xx CFW, it utilizes the additional ram that the slim comes with. With that, my fat PSP run's the program ok, but does suffer an occasional freeze in mid play, something that supposedly does not occur on a slim with this software.

I just figured I'd throw out the question, has anyone tried to physically replace the ram inside of there PSP? Would it be possible?