Is the psp 2001 slim, with serial num ab025 finally hackable so I can put CFW on it?

i bought a psp slim 2001 from a guy today...its mint condition, he said it already had the CFW on it, but I have been unable to put any games on it so far...i read recently that anything with the serial ab021 and higher is not hackable but this post was dated 2008...is this still true?