I have looked everywhere for this information, and I can't find anything on the subject. I just bought a PSP with firmware 1.5 from a seller on the internet, and the seller states that this PSP cannot be upgraded beyond 3.5 firmware. I have never heard of this, and I want to upgrade to 3.52 m33-4. Are there any PSP 1.5's that can't be upgraded past 3.5? If anyone could explain a reason why this seller's statement is true or false, please let me know. Thank you!