I have a PSP with 3.50 firmware and i would like to downgrade it to version 1.50. I used lots of downgraders but everywhere you need Lumines game. I downloaded it and it is in .iso file. I tried to get it on my psp but the psp won't recognise it and it writes corrupted file when I try to open it... Would you help me I'm desperate already. Thank you very much!